Key to Strumigenys of East Asia

This worker key is based on: Bolton, B. 2000. The ant tribe Dacetini. Memoirs of the American Entomological Institute. 65:1-1028.

Malasian-Oriental-East Palaearctic Strumigenys

Bolton noted: Note. The Tongan Strumigenys zakharovi (species inquirenda) is not included in the key.

This key is from a study that included the now synonymized genus Pyramica. Therefore there are two sets of keys for the Strumigenys species from this region: the key found below and this second key for the species once classified as Pyramica: and a key Key to Strumigenys of East Asia (as Pyramica).

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 * Strumigenys

1

 * Antenna with 4 segments; first funicular segment not separated from the 2-segmented apical club . . . . . 2


 * Antenna with 6 segments; first funicular segment separated from the 2-segmented apical club by two small segments . . . . . 6

2
return to couplet #1
 * Pronotal humeral hair absent . . . . . 3


 * Pronotal humeral hair present, stiff and simple . . . . . 4

3
return to couplet #2
 * Leading edge of scape expanded into a massive projecting lobe, the area of which is much greater than the area of the median portion of the clypeus; SL at most 1.60 times the maximum scape width. Apical segment of antenna not spindle-shaped, broad basally where it articulates with preapical segment. (Indonesia (Sulawesi, Kai Besar), Papua New Guinea, Solomon Is) . . . . . Strumigenys eurycera


 * Leading edge of scape shallowly convex, not expanded into a massive projecting lobe that is greater in area than median portion of clypeus; SL 5.00 times the maximum scape width. Apical segment of antenna spindle-shaped, very constricted and narrow basally where it articulates with preapical segment. (Papua New Guinea) . . . . . Strumigenys pharosa

4
return to couplet #2
 * Basal half of first gastral sternite unsculptured. Cephalic dorsum with numerous orbicular hairs, without erect simple hairs. Leading edge of scape with short spatulate or spoon-shaped hairs that are shorter than maximum width of scape. (Pantropical tramp species) . . . . . Strumigenys emmae

5
return to couplet #5
 * Pronotum and mesonotum each with a single pair of short erect hairs. With head in full-face view dorsolateral margin with only 2-3 laterally projecting stiff hairs. Mesopleuron partly smooth. (Papua New Guinea) . . . . . Strumigenys quattuor


 * Pronotum and mesonotum each with numerous short erect hairs. With head in full-face view dorsolateral margin with more than 5 laterally projecting stiff hairs. Mesopleuron entirely reticulate-punctate. (Papua New Guinea) . . . . . Strumigenys tetra

6
return to couplet #1
 * With petiole in profile the ventral surface without any trace of a longitudinal spongiform or laminate crest, lamella or curtain . . . . . 7


 * With petiole in profile the ventral surface with a longitudinal spongiform or laminate crest, lamella or curtain present; may be narrow or sometimes reduced to a small lobe or narrow strip beneath the node . . . . . 16


 * Basal half of first gastral sternite longitudinally costulate. Cephalic dorsum with numerous short erect simple hairs, without orbicular hairs. Leading edge of scape with simple curved hairs that are longer than maximum width of scape . . . . . 5

7
return to couplet #6
 * Postpetiole in profile with ventral spongiform lobe large and well developed; lobe broadly triangular to broadly rounded and at least equal in size to the exposed cuticle of the disc . . . . . 8


 * Postpetiole in profile with ventral lobe vestigial to absent; when vestigially present the lobe not broadly triangular nor broadly rounded and very much smaller than the exposed cuticle of the disc . . . . . 9

8
return to couplet #7
 * Head, alitrunk and disc of postpetiole smooth and shining. In full-face view ventrolateral margin of head deeply excavated immediately in front of the eye. Declivity of propodeum with a broad lamella, its posterior (free) margin convex. Basigastral costulae short, restricted to zone immediately behind limbus. Head broad, scape shorter; CI 95, SI 55. (Indonesia (Sulawesi)) . . . . . Strumigenys zapyx


 * Head, alitrunk and disc of postpetiole reticulate-punctate. In full-face view ventrolateral margin of head not excavated immediately in front of the eye. Declivity of propodeum with a narrow carina, its posterior (free) margin concave. Basigastral costulae long, extending over the basal half of the tergite. Head narrow, scape longer; CI 70, SI 82. (Papua New Guinea) . . . . . Strumigenys wilsoni

9
return to couplet #7
 * With alitrunk in dorsal view pronotum and anterior mesonotum black or blackish brown, propodeal dorsum and usually also posterior portion of mesonotum yellow, the two colour zones strongly contrasting . . . . . 10


 * With alitrunk in dorsal view entire surface more or less uniformly coloured yellow, brown or black, without strongly contrasting zones of black and yellow . . . . . 12

10
return to couplet #9
 * Ventrolateral margin of head deeply notched or impressed immediately in front of eye, the notch or impression continued onto the ventral surface of the head as a transverse preocular groove or impression that extends toward, but does not reach, the midline . . . . . 11


 * Ventrolateral margin of head not deeply notched or impressed immediately in front of eye; the ventral surface of the head without a transverse preocular groove or impression that extends toward the midline. (Papua New Guinea) . . . . . Strumigenys yasumatsui

11
return to couplet #10
 * Petiole and postpetiole black. Petiole in profile with anterior face of node meeting dorsum in a long shallow convexity, the dorsum much longer than the anterior face. (Papua New Guinea) . . . . . Strumigenys tigris


 * Petiole and postpetiole yellow. Petiole in profile with anterior face of node meeting dorsum in a blunt angle, the dorsum only slightly longer than the anterior face. (Indonesia (Irian Jaya), Papua New Guinea) . . . . . Strumigenys hemichlaena

12
return to couplet #9
 * Propodeal teeth absent in profile, the angle between dorsum and declivity unarmed or with a pair of minute blunt tubercles; in dorsal view the tubercles much shorter than the distance separating them. (Papua New Guinea) . . . . . Strumigenys disarmata


 * Propodeal teeth or spines conspicuous in profile, narrowly triangular and acute; in dorsal view the teeth equal to or greater in length than the distance separating them . . . . . 13

13
return to couplet #12
 * Head, alitrunk and waist segments yellow to light yellow-brown everywhere; gaster may be same shade or darker . . . . . 14


 * Head, alitrunk and waist segments black to blackish brown everywhere; gaster also black or blackish brown. (Papua New Guinea) . . . . . Strumigenys nigra

14
return to couplet #13
 * Side of alitrunk completely smooth and shining, without trace of reticulate-punctate sculpture. (Papua New Guinea) . . . . . Strumigenys lancea


 * Side of alitrunk almost entirely reticulate-punctate, at most with a smooth patch on katepisternum . . . . . 15

15
return to couplet #14
 * Hairs of apical row on first gastral tergite and hairs on second gastral tergite flagellate, contrasting with the straight stiff hairs on the postpetiole. Propodeal spines long and slender, twice as long as the distance between their bases. Larger species, HL > 1.00. (Indonesia (Kai Besar), Papua New Guinea, Palau) . . . . . Strumigenys stemonixys


 * Hairs of apical row on first gastral tergite and hairs on second gastral tergite simple, short and stiff, the same as those on the postpetiole. Propodeal spines shorter, about equal to distance between their bases or less. Smaller species, HL < 1.00. (Singapore, Philippines (Mindanao, Luzon, Mindoro, Negros), Indonesia (Sulawesi, Kai Besar, Aru, Irian Jaya), Papua New Guinea, Solomon Is, Vanuatu, Samoa, Ponape I.; also in Australia) . . . . . Strumigenys szalayi

16
return to couplet #6
 * Ventrolateral margin of head at level of eye extended outward and downward, forming an acutely triangular prominence. Eye located on dorsal surface of this prominence; acute apex of prominence extends out beyond the midlength of the eye in the form of a sharp point . . . . . 17


 * Ventrolateral margin of head at level of eye regular or with a preocular notch or impression, but not extended outward and downward as an acutely triangular prominence. Eye not located on dorsal surface of a triangular prominence and without a sharp point that extends out beyond the midlength of the eye . . . . . 19

17
return to couplet #16
 * Erect hairs on cephalic dorsum stiff and shallowly curved, apically truncated and slightly splayed or minutely bifid. (Malaysia (Sarawak)) . . . . . Strumigenys akalles


 * Erect hairs on cephalic dorsum fine, soft and flexuous, apically tapering to acute points . . . . . 18

18
return to couplet #17
 * With mandibles fully closed the proximal preapical tooth of the left mandible is longer than the distance between its base and the anterior clypeal margin. Clypeus and pronotal dorsum smooth and shining. (Malaysia (West Malaysia), Indonesia (Java)) . . . . . Strumigenys eidechthes


 * With mandibles fully closed the proximal preapical tooth of the left mandible is much shorter than the distance between its base and the anterior clypeal margin. Clypeus and pronotal dorsum finely sculptured. (Malaysia (West Malaysia, Sarawak, Sabah), Indonesia (Sumatra, Sulawesi), Philippines (Luzo)) . . . . . Strumigenys inhonesta

19
return to couplet #16
 * Apex of mandible with three short-spiniform to long-spiniform teeth arranged in a vertical or oblique series (series may be extremely oblique so that lowermost tooth has migrated onto ventral surface and appears as a ventrally-arising preapical tooth in full-face view); with 0-2 intercalary denticles or small teeth, which when present arise between apicomedian and apicoventral teeth or from dorsal surface of apicoventral tooth . . . . . 20


 * Apex of mandible with two spiniform teeth arranged in a vertical or near-vertical series; with 0-3 intercalary denticles or small teeth, which when present arise between the apicodorsal and apicoventral teeth or from dorsal surface of apicoventral tooth near its base . . . . . 35

20
return to couplet #19
 * Fully closed mandible in full-face view very broad proximally and strikingly tapered distally, obviously not linear or curvilinear. Outer margin of mandible flared outwards near base and with a strongly projecting prebasal angle. In ventral view outer margin of mandible distal of level of anterior clypeal margin abruptly changing direction . . . . . 21


 * Fully closed mandible in full-face view not very broad proximally nor strikingly tapered distally, linear or curvilinear, sometimes weakly sinuate. Outer margin of mandible not flared outwards near base, without a strongly projecting prebasal angle. In ventral view outer margin of mandible forms a more or less continuous line that does not abruptly change direction distal of level of anterior clypeal margin . . . . . 30

21
return to couplet #20
 * With alitrunk in dorsal view pronotal humeral hair absent . . . . . 22


 * With alitrunk in dorsal view pronotal humeral hair present, projecting laterally; hair straight, simple or clavate, may be elongate or short and stout . . . . . 24

22
return to couplet #21
 * With head in full-face view apicoscrobal hair present, very short and stubbly. Appressed hairs on first gastral tergite fine, very narrowly spatulate and inconspicuous . . . . . 23


 * With head in full-face view apicoscrobal hair absent. Appressed hairs on first gastral tergite distinctly spatulate, numerous and conspicuous. (Malaysia (Sarawak), Indonesia (Kalimantan)) . . . . . Strumigenys aechme

23
return to couplet #22
 * Postpetiole disc in dorsal view much broader than petiole node. Small species, HW ca 0.47. (Sri Lanka, India, Bhutan) . . . . . Strumigenys lyroessa


 * Postpetiole disc in dorsal view about equal to petiole node width. Larger species, HW 0.56-0.61. (Malaysia (West Malaysia)) . . . . . Strumigenys tantilla

24
return to couplet #21
 * Dorsal surfaces of pronotum and mesonotum with numerous short straight erect stubbly hairs; similar hairs also present on dorsolateral margins of mesonotum. (Indonesia (Sulawesi)) . . . . . Strumigenys dryas


 * Dorsal surfaces of pronotum and mesonotum without erect hairs; dorsolateral margins of the mesonotum either hairless or at most with 2-3 short erect hairs on each margin . . . . . 25

25
return to couplet #24
 * Scape relatively long and head narrower, SI 67-71, CI 68-71; hind femur elongate, about equal to HW. (Malaysia (Sabah)) . . . . . Strumigenys liophila


 * Scape relatively short and head broader, SI 50-57, CI 72-84; hind femur short, much less than HW . . . . . 26

26
return to couplet #25
 * First gastral tergite entirely covered with fine dense longitudinal striolate-punctulate sculpture. Eye with 7-8 ommatidia in longest row; maximum diameter of eye obviously greater than maximum width of scape. Larger species, HL 0.89-0.92, HW 0.73-0.76. (India) . . . . . Strumigenys hostilis


 * First gastral tergite un sculptured except for basigastral costulae. Eye with 3-5 ommatidia in longest row; maximum diameter of eye at most equal to maximum width of scape, usually less. Smaller species, HL 0.62-0.80, HW 0.47-0.62 . . . . . 27

27
return to couplet #26
 * Lamella on propodeal declivity very narrow in profile; at its broadest point below the level of the spiracle it is less than half the length of the propodeal tooth . . . . . 28


 * Lamella on propodeal declivity broader in profile; at its broadest point below the level of the spiracle it is distinctly more than half the length of the propodeal tooth . . . . . 29

28
return to couplet #27
 * Petiole node in dorsal view about as broad as long, not transversely rectangular. Larger black species, HL 0.77-0.80, HW 0.60-0.62. (Malaysia (West Malaysia)) . . . . . Strumigenys micrura


 * Petiole node in dorsal view much broader than long, transversely rectangular. Smaller light brown species, HL 0.65, HW 0.49. (Indonesia (Sulawesi)) . . . . . Strumigenys imantodes

29
return to couplet #27
 * Mandible in profile with preapical tooth strongly developed, broader-based and stouter than the apicodorsal tooth; dorsal margin of mandible depressed distal of preapical tooth so that space between the two teeth appears as a cleft. (Thailand, Malaysia (West Malaysia), Indonesia (Java, Lombok)) . . . . . Strumigenys sydorata


 * Mandible in profile with preapical tooth about the same shape and size as the apicodorsal tooth; dorsal margin of mandible not depressed distal of preapical tooth, space between the two teeth appears as a short transverse margin. (Malaysia (Sarawak, Sabah), Indonesia (Kalimantan, Thnimbar), Philippines (Palawan, Luzon)) . . . . . Strumigenys arrogantia

30
return to couplet #20
 * Hairs on first gastral tergite flagellate, elongate and fine, slender and acute apically. Intercalary denticles absent between apicomedian and apicoventral spiniform teeth although a minute denticle may arise from about the dorsal midlength of the apicoventral tooth . . . . . 31


 * Hairs on first gastral tergite stiff, either simple, remiform or spatulate, straight to shallowly curved and blunt apically. One or two intercalary denticles present between apicomedian and apicoventral spiniform teeth or arising from near base of apicoventral tooth on its dorsal surface . . . . . 33

31
return to couplet #30
 * Head extremely broad, almost or quite as broad as long, CI ca 100. With head in full-face view the apical series of mandibular teeth extremely oblique, so that the apicoventral tooth arises preapically from the ventral surface of the mandible. Hairs on postpetiole flagellate, the same as those on first gastral tergite . . . . . 32


 * Head elongate, obviously longer than broad, CI ca 75. With head in full-face view the apical series of mandibular teeth nearly vertical, the apicoventral tooth does not arise preapically from the ventral surface of the mandible. Hairs on postpetiole stiff and remiform, contrasting strongly with the long flagellate hairs on first gastral tergite. (Malaysia (Sarawak, Sabah)) . . . . . Strumigenys trixodens

32
return to couplet #31
 * Mandibles shorter and stouter, MI 45-51. Length of apicodorsal tooth of mandible (measured from apex to junction with inner margin of mandible) 2.00-2.25 times the maximum mandibular width. Scape slightly shorter, SI 43-50. (Thailand, Malaysia (West Malaysia, Sarawak, Sabah), Brunei, Indonesia (Sumatra)) . . . . . Strumigenys rotogenys


 * Mandibles longer and narrower, MI 56-57. Length of apicodorsal tooth of mandible (measured from apex to junction with inner margin of mandible) 2.80-3.10 times the maximum mandibular width. Scape slightly longer, SI 51-54. (Malaysia (Sarawak)) . . . . . Strumigenys gyrogenys

33
return to couplet #30
 * Inner margin of mandible with a broad translucent cuticular lamella that extends from base of mandible to near base of apicodorsal tooth; at full closure inner margins very nearly touching throughout their length. (Thailand) . . . . . Strumigenys tritomea


 * Inner margin of mandible without a cuticular lamella; at full closure inner margins widely separated throughout their length . . . . . 34

34
return to couplet #33
 * Pleurae and side of propodeum mostly or entirely smooth. Dorsal (outer) surface of hind basitarsus with a number of projecting long straight hairs that are filiform to weakly remiform and about three times longer than the maximum width of the basitarsus. (Malaysia (West Malaysia, Sarawak), Philippines (Luzon), Indonesia (Sulawesi)) . . . . . Strumigenys chapmani


 * Pleurae and side of propodeum entirely finely reticulate-punctate. Dorsal (outer) surface of hind basitarsus with relatively short curved spatulate hairs that are somewhat elevated and only slightly longer than the maximum width of the basitarsus. (Malaysia (Sarawak)) . . . . . Strumigenys treptodens

35
return to couplet #19 enormous, at least equal to the maximum width of the first coxa . . . . . 36
 * With alitrunk in profile the diameter of the excavated area of the mesopleural gland


 * With alitrunk in profile the diameter of the excavated area of the mesopleural gland small to moderate, much less than the maximum width of the first coxa . . . . . 42

36
return to couplet #35
 * With petiole in profile, and also in dorsal view, the lateral spongiform lobe of the node extends forward to about the level of the spiracle on the peduncle . . . . . 37


 * With petiole in profile, and also in dorsal view, the lateral spongiform lobe is confined to the node and does not extend forward to the spiracle on the peduncle . . . . . 40

37
return to couplet #36
 * Mandible with a small but distinct preapical tooth. (Philippines (Luzon)) . . . . . Strumigenys mirifica


 * Mandible without trace of preapical teeth or denticles . . . . . 38

38
return to couplet #37
 * Head in profile with extremely long erect hairs arising from the highest point of the dorsum and also from the surface anterior to the highest point; these hairs as long as those that arise close to the occipital margin. With mandible in frontal view curve between bases of apicodorsal and apicoventral teeth wide and very broadly V-shaped. With alitrunk in profile glandular excavation in anterior margin of mesopleuron usually distinctly longer than remaining length of katepisternum. Head narrower, scape longer, CI 57-64, SI 103-128 . . . . . 39


 * Head in profile with hairs that arise in front of highest point of dorsum much shorter than those arising more posteriorly. With mandible in frontal view angle between bases of apicodorsal and apicoventral teeth V-shaped to narrowly V-shaped. With alitrunk in profile glandular excavation in anterior margin of mesopleuron usually slightly shorter than remaining length of katepisternum. Head broader, scape shorter, CI 66-74, SI 86-97. (Thailand, Malaysia (West Malaysia, Sarawak, Sabah), Indonesia (Sumatra, Java, Bali, Lombok, Sumba, Ambon, Sulawesi, Timor)) . . . . . Strumigenys doriae

39
return to couplet #38
 * In oblique dorsal view side of propodeum without dense standing pubescence that obscures the spiracle. Short grey pubescence on dorsal alitrunk relatively sparse on pronotum and propodeum, these areas without a furry appearance. (Malaysia (West Malaysia, Sarawak)) . . . . . Strumigenys magnifica


 * In oblique dorsal view side of propodeum with dense standing pubescence that obscures the spiracle. Short grey pubescence on dorsal alitrunk very dense on pronotum and propodeum, these areas with a furry appearance. (Malaysia (Sabah), Brunei) . . . . . Strumigenys gloriosa

40
return to couplet #36
 * Mandible with 2 minute preapical denticles. Surface of first gastral tergite with dense appressed grey pubescence between the bases of the erect flagellate hairs. In dorsal view pronotal humeri angulate. (Malaysia (Sabah)) . . . . . Strumigenys hekate


 * Mandible without trace of preapical denticles. Surface of first gastral tergite without pubescence between the bases of the erect flagellate hairs. In dorsal view pronotal humeri rounded . . . . . 41

41
return to couplet #40
 * With mandible in frontal view angle between bases of apicodorsal and apicoventral teeth very broadly V-shaped; apicoventral tooth about same length as apicodorsal. Head narrower, mandibles shorter and scapes longer, CI 57-60, MI 46-48, SI 112-118. (Malaysia (Sarawak)) . . . . . Strumigenys superba


 * With mandible in frontal view angle between bases of apicodorsdal and apicoventral teeth narrow and V-shaped; apicoventral tooth much shorter than apicodorsal. Head broader, mandibles longer and scapes shorter, CI 65, MI 53, SI 99. (Malaysia (Sarawak, Sabah)) . . . . . Strumigenys bryanti

42
return to couplet #35
 * Preapical dentition of each mandible of two articles; either with 2 preapical teeth or with one tooth and a denticle . . . . . 43


 * Preapical dentition of each mandible either absent or of a single article; when present with either a single tooth or a single denticle . . . . . 47

43
return to couplet #42
 * Proximal preapical tooth much shorter than distal preapical tooth, the former in the basal half of the mandible length. Mesonotum and first gastral tergite without standing hairs . . . . . 44


 * Proximal preapical tooth longer than distal preapical tooth, both in the apical third of the mandible length. Mesonotum and first gastral tergite with standing hairs . . . . . 45

44
return to couplet #43
 * With petiole in profile the node with a short steeply ascending anterior face that separates the peduncle from the dorsum. Cephalic dorsum feebly superficially shagreenate on posterior half, without ground-pilosity and without a pair of erect hairs at highest point of vertex. (Solomon Is) . . . . . Strumigenys decollata


 * With petiole in profile the node without a steeply ascending anterior face, the peduncle grading into the dorsum through a shallowly convex long even curve. Cephalic dorsum reticulate-rugulose on posterior half, with spatulate ground-pilosity and with a pair of erect hairs at highest point of vertex. (Papua New Guinea) . . . . . Strumigenys praecollata

45
return to couplet #43
 * Ventrolateral margin of the head deeply indented immediately in front of the eye, so deeply that the anterior portion of the eye is detached from the side of the head. Ventral surface of head with a transverse preocular impression that is posterior to and separate from the postbuccal groove. (Cosmopolitan tramp species) . . . . . Strumigenys rogeri


 * Ventrolateral margin of the head continuous to the anterior margin of the eye, without trace of an indentation of the margin immediately in front of the eye. Ventral surface of head without a transverse preocular impression that is posterior to and separate from the postbuccal groove . . . . . 46

46
return to couplet #45
 * With postpetiole in profile its ventral spongiform lobe smaller than the exposed cuticle of the swollen disc. Larger species, HL 0.60-0.64, HW 0.46-0.48. (Indonesia (Timor)) . . . . . Strumigenys integra


 * With postpetiole in profile its ventral spongiform lobe larger than the exposed cuticle of the disc. Smaller species, HL 0.49-0.55, HW 0.40-0.43. (Indonesia (Bali, Lombok) . . . . . Strumigenys yanintra

47
return to couplet #42
 * With head in full-face view mandible without preapical dentition, no trace of a projecting preapical tooth or denticle . . . . . 48


 * With head in full-face view mandible with preapical dentition, a projecting preapical tooth or denticle present . . . . . 54

48
return to couplet #47
 * Dorsal (outer) surface of middle and hind basi tarsus with two or more very long projecting suberect to erect hairs that are finely filiform or flagellate and very much longer than the maximum width of the segment from which they arise. First gastral tergite with fine soft filiform to flagellate hairs . . . . . 49


 * Dorsal (outer) surface of middle and hind basitarsus without long projecting suberect to erect hairs; any pilosity present is short, simple to spatulate and decumbent to appressed. First gastral tergite with stiff simple blunt hairs . . . . . 52

49
return to couplet #48
 * First gastral tergite with dense appressed greyish pubescence covering the sclerite between the bases of the erect long hairs. (Malaysia (Sarawak), Brunei) . . . . . Strumigenys cygarix


 * First gastral tergite with the surface bare between the bases of the erect long hairs, without any appressed pubescence . . . . . 50

50
return to couplet #49
 * Side of alitrunk evenly longitudinally sulcate everywhere. Coxa of front leg transversely sulcate. (Thailand) . . . . . Strumigenys caniophanes


 * Side of alitrunk without sulcate sculpture; side either finely granulate or punctate, or partly smooth. Coxa of front leg not sulcate . . . . . 51

51
return to couplet #50
 * Mesopleuron entirely reticulate-punctate. Petiole node in dorsal view slightly broader than long. Scape relatively longer, SI 84. (Malaysia (Sabah)) . . . . . Strumigenys dromica


 * Mesopleuron mostly smooth and shining. Petiole node in dorsal view longer than broad. Scape relatively shorter, SI 71. (China) . . . . . Strumigenys heteropha

52
return to couplet #48
 * Ventrolateral margin of head with a deep semicircular impression immediately in front of the eye. Apicoventral tooth of mandible vertically below apicodorsal tooth. Side of alitrunk mostly or entirely reticulate-punctate . . . . . 53


 * Ventrolateral margin of head continuous in front of the eye, without a semicircular impression. Apicoventral tooth of mandible shifted proximally, not vertically below apicodorsal tooth. Side of alitrunk mostly un sculptured and smooth. (Malaysia (Sabah), Indonesia (Sumatra)) . . . . . Strumigenys ochosa

53
return to couplet #52
 * Disc of postpetiole reticulate-punctate. Petiole node longer than broad in dorsal view. Dorsolateral margin of head in full-face view with two laterally projecting stiff long hairs between level of eye and occipital corner; one at level of eye, the other apicoscrobal. With narrower head and longer scape and mandibles; CI < 75, SI > 90, MI > 45. (Indonesia (Aru)) . . . . . Strumigenys rayma


 * Disc of postpetiole u n sculptured and smooth. Petiole node broader than long in dorsal view. Dorsolateral margin of head in full-face view with four or more laterally projecting short stubbly hairs between level of eye and occipital corner. With broader head and shorter scape and mandibles; CI > 80, SI < 70, MI < 45. (Papua New Guinea) . . . . . Strumigenys pachycephala

54
return to couplet #47
 * Dorsal (outer) surface of hind basitarsus with one or more freely projecting filiform or flagellate hairs that are very long and suberect to erect; this specialised pilosity may also be present on the middle basi tarsus and the middle and hind tibiae . . . . . 55


 * Dorsal (outer) surface of hind basitarsus without freely projecting long filiform or flagellate hairs; any pilosity present is simple to spatulate and usually decumbent to appressed; projecting long fine simple hairs absent from middle basi tarsus and from middle and hind tibiae . . . . . 130

55
return to couplet #54
 * Entire dorsum of alitrunk and entire side of alitrunk except for katepisternum (which is smooth) covered with flocculent or spongiform tissue, this tissue arranged in closeset raised clumps and patches which have only very narrow channels between them. (Papua New Guinea) . . . . . Strumigenys sisyrata


 * Dorsum and sides of alitrunk not covered with close-set raised clumps and patches of flocculent or spongiform tissue; in general such tissue absent from alitrunk but sometimes lamella of propodeal declivity is spongiform . . . . . 56

56
return to couplet #55
 * First gastral tergite entirely covered with fine dense longitudinal sulcate sculpture; no other form of sculpture present on sclerite, differentiated basigastral costulae absent. (Fiji Is) . . . . . Strumigenys panaulax


 * First gastral tergite not entirely covered with longitudinal sulcate sculpture; tergite usually with basigastral costulae that may extend up to half the length of the sclerite, which is usually un sculptured posteriorly; rarely tergite entirely smooth or with another form of sculpture distal of the basigastral costulae . . . . . 57

57
return to couplet #56
 * With alitrunk in profile the propodeal declivity equipped with a broad and conspicuous lamella; the propodeal tooth may be replaced by the lamella or completely buried in the lamella, or the lamella may subtend the ventral margin of the tooth for most or all of its length; posterior (free) margin of lamella may be convex, straight or irregular but is not narrowly concave, nor is it close to and parallel with the edge of the declivity . . . . . 58


 * With alitrunk in profile the propodeal declivity equipped with a simple carina or at most a narrow cuticular flange; carina or narrow flange does not subtend the ventral margin of the tooth for most or all of its length; posterior (free) margin of carina or narrow flange concave, close to and parallel with the edge of the . . . . . 99

58
return to couplet #57
 * With head in full-face view the upper scrobe margin with two or more flagellate or filiform hairs that freely project laterally; at least with one in apicoscrobal position and another anterior to this (dorsolateral margin of occipital lobe posterior to apex of scrobe may have additional laterally projecting hairs) . . . . . 59


 * With head in full-face view the upper scrobe margin usually with a single hair that freely projects laterally, in apicoscrobal position; this hair may be flagellate, filiform, or short and stiff; sometimes without a hair in this position (dorsolateral margin of occipital lobe posterior to apex of scrobe may have laterally projecting hairs) . . . . . 62

59
return to couplet #58
 * Disc of postpetiole finely and densely longitudinally striate-costulate. Basigastral costulae longer than disc of postpetiole, extending almost half the length of the first gastral tergite. (Fiji Is) . . . . . Strumigenys chernovi


 * Disc of postpetiole smooth and shining. Basigastral costulae shorter than disc of postpetiole, extending much less than half the length of the first gastral tergite . . . . . 60

60
return to couplet #59
 * With head in profile standing pilosity on cephalic dorsum restricted to 1-2 pairs of erect fine flagellate hairs. Pronotal dorsum densely reticulate-punctate. (Indonesia (Tanimbar, Aru, Irian Jaya), Papua New Guinea, Solomon Is; also in Australia) . . . . . Strumigenys yaleopleura


 * With head in profile standing pilosity on cephalic dorsum of numerous short stiff hairs that arise all over the surface from the level of the eye to the occipital margin. Pronotal dorsum smooth or with superficial fine sculpture . . . . . 61

61
return to couplet #60
 * Head unsculptured and smooth mediodorsally. Hairs on leading edge of scape short, fine and soft, decumbent and strongly curved toward apex of scape, much shorter than maximum width of scape' Mesonotum with a single pair of erect hairs. Erect hairs on first gastral tergite restricted to a single basal and a single apical transverse row. (Malaysia (Sabah)) . . . . . Strumigenys hastur


 * Head entirely reticulate-punctate. Hairs on leading edge of scape elongate, stout and stiff, suberect and only shallowly curved toward apex of scape, about as long as maximum width of scape. Mesonotum with a several pairs of erect hairs. Erect hairs on first gastral tergite arising over entire sclerite, not restricted to apical and basal rows. (Taiwan) . . . . . Strumigenys liukueiensis

62
return to couplet #58
 * Fully closed mandible in full-face view broad proximally and strikingly tapered distally, not linear or curvilinear; mandibles short, MI 28-32. Apicoscrobal hair absent and first gastral tergite with hairs restricted to extreme base and extreme apex . . . . . 63


 * Fully closed mandible in full-face view linear or curvilinear, sometimes slightly increasing in width toward base; mandibles longer, MI 34-58. Either apicoscrobal hair present, or first gastral tergite with hairs not restricted to extreme base and extreme apex, or both of these . . . . . 64

63
return to couplet #62 often also completely sculptured but in some a part of this sclerite may be smooth. (Papua New Guinea). . . . . Strumigenys pulchra
 * Metapleuron and side of propodeum mostly to entirely reticulate-punctate. Mesopleuron


 * Metapleuron and side of propodeum glassy smooth, at most with weak sculpture around extreme periphery. Mesopleuron always glassy smooth. (Indonesia (Aru), Papua New Guinea) . . . . . Strumigenys biroi

64
return to couplet #62
 * Metapleuron and side of propodeum evenly densely reticulate-punctate everywhere. Mesopleuron often also completely sculptured but in some a part or most of this sclerite may be smooth . . . . . 65


 * Metapleuron and side of propodeum partially to entirely smooth; often with weak punctulate sculpture around periphery or with some faint shallow superficial shagreening. Mesopleuron always glassy smooth . . . . . 75

65
return to couplet #64
 * With petiole in profile the lateral spongiform lobe small and restricted to posterior portion of node; dorsal margin of lateral spongiform lobe does not extend forward to level of anterior face of node . . . . . 66


 * With petiole in profile the lateral spongiform lobe large, not restricted to posterior portion of node; dorsal margin of lateral spongiform lobe extends across most or all of the side of the segment, approaching or reaching level of anterior face of node . . . . . 71

66
return to couplet #65
 * Pronotal humeral hair long, fine and flagellate . . . . . 67


 * Pronotal humeral hair short, stiff or stout and blunt . . . . . 70

67
return to couplet #66
 * Disc of postpetiole coarsely longitudinally costulate, spaces between costulae finely reticulate-punctate. Basigastral costulae extending about half the length of the sclerite. First gastral tergite with sparse fine flagellate hairs. (Phillipines) . . . . . Strumigenys phytibia


 * Disc of postpetiole shagreenate to reticulate-punctate, without coarse longitudinal costulae. Basigastral costulae distinctly shorter than half the length of the sclerite. First gastral tergite with numerous stiff hairs that are suberect to erect and mostly short . . . . . 68

68
return to couplet #67
 * With head in full-face view upper scrobe margin confluent with dorsolateral margin of occipital lobe, the two together forming a single evenly convex line; ventrolateral margin of head behind eye not visible in this view. Inner margin of mandible bearing a narrow translucent cuticular crest in about the median third of its length . . . . . 69


 * With head in full-face view upper scrobe margin not confluent with dorsolateral margin of occipital lobe, the two together not forming a single evenly convex line; ventrolateral margin of head behind eye visible in this view. Inner margin of mandible without a cuticular crest in about the median third of its length. (Malaysia (West Malaysia) . . . . . Strumigenys epyna

69
return to couplet #68
 * Hairs on second gastral tergite stiff and feebly remiform. Base of first gastral tergite without flagellate hairs. Mandibles shorter, MI 38-41. (Malaysia (West Malaysia)) . . . . . Strumigenys phoenix


 * Hairs on second gastral tergite flagellate. Base of first gastral tergite with 1-2 pairs of flagellate hairs. Mandibles longer, MI 45-46. (Brunei) . . . . . Strumigenys zagan

70
return to couplet #66
 * Apicoscrobal hair absent. Pronotal dorsum without a pair of erect remiform hairs between the humeral pair. Hairs on first gastral tergite spatulate, curved and strongly inclined posteriorly. (Malaysia (West Malaysia), Indonesia (Sulawesi)) . . . . . Strumigenys nesteryx


 * Apicoscrobal hair present, stout. Pronotal dorsum with a pair of erect short remiform hairs between the humeral pair. Hairs on first gastral tergite remiform, suberect. (Malaysia (Sarawak)) . . . . . Strumigenys mjoebergi

71
return to couplet #65
 * Basigastral costulae dense and long, extending over at least the basal half of the first gastral tergite. (Japan) . . . . . Strumigenys strigatella


 * Basigastral costufae sparse and short, much shorter than half the length of the first gastral tergite . . . . . 72

72
return to couplet #71
 * Apicoscrobal hair short and stiff, not flagellate. Hairs on first gastral tergite short and fine. Mesopleuron mostly smooth. (Malaysia (Sabah)) . . . . . Strumigenys dyak


 * Apicoscrobal hair flagellate. Hairs on first gastral tergite long and flagellate. Mesopleuron mostly or entirely sculptured . . . . . 73

73
return to couplet #73
 * Propodeal teeth in profile well developed, not entirely embedded in the lamella on the declivity, without a crest of spongiform tissue along dorsum of tooth. Propodeal teeth in dorsal view appearing cuticular. Disc of postpetiole densely reticulate-punctate. (Indonesia (Sulawesi)) . . . . . Strumigenys asrochia


 * Propodeal teeth in profile poorly represented or vestigial, entirely embedded in the thick spongiform lamella on the declivity and with a crest of spongiform tissue along dorsum of tooth. Propodeal teeth in dorsal view appearing spongiform. Disc of postpetiole un sculptured or at most with very fine superficial markings, not densely reticulate-punctate . . . . . 74

74
return to couplet #73
 * Pronotal dorsum with 1-2 pairs of erect flagellate hairs, as well as the humeral pair. Mesonotum with 1-2 (rarely 3) pairs of erect flagellate hairs. MI 42-45, SI 85-93. (Thailand, Malaysia (West Malaysia)) . . . . . Strumigenys confusatrix

- Pronotal dorsum without erect flagellate hairs apart from the humeral pair. Mesonotum with a single pair of erect flagellate hairs. MI 48-53, SI 93-102. (Malaysia (West Malaysia, Sarawak, Sabah), Brunei, Indonesia (Sumatra), Philippines (Palawan)). . . . . ''[[Strumigenys

73
return to couplet #73
 * Propodeal teeth in profile well developed, not entirely embedded in the lamella on the declivity, without a crest of spongiform tissue along dorsum of tooth. Propodeal teeth in dorsal view appearing cuticular. Disc of postpetiole densely reticulate-punctate. (Indonesia (Sulawesi)) . . . . . Strumigenys asrochia


 * Propodeal teeth in profile poorly represented or vestigial, entirely embedded in the thick spongiform lamella on the declivity and with a crest of spongiform tissue along dorsum of tooth. Propodeal teeth in dorsal view appearing spongiform. Disc of postpetiole un sculptured or at most with very fine superficial markings, not densely reticulate-punctate . . . . . 74

74
return to couplet #73
 * Pronotal dorsum with 1-2 pairs of erect flagellate hairs, as well as the humeral pair. Mesonotum with 1-2 (rarely 3) pairs of erect flagellate hairs. MI 42-45, SI 85-93. (Thailand, Malaysia (West Malaysia)) . . . . . Strumigenys confusatrix

- Pronotal dorsum without erect flagellate hairs apart from the humeral pair. Mesonotum with a single pair of erect flagellate hairs. MI 48-53, SI 93-102. (Malaysia (West Malaysia, Sarawak, Sabah), Brunei, Indonesia (Sumatra), Philippines (Palawan)). . . . . Strumigenys indagatrix

75
return to couplet #64
 * With alitrunk in profile dorsum of pronotum without standing hairs apart from the humeral hair . . . . . 76


 * With alitrunk in profile dorsum of pronotum with usually one other pair of standing hairs as well as the humeral hair; rarely with more than one pair . . . . . 79

76
return to couplet #75
 * Apicoscrobal hair present and long, filiform or flagellate; this hair very different in form and length from any other on the margin both anterior and posterior to it . . . . . 77


 * Apicoscrobal hair absent; entire margin with a dense row of uniformly shaped small curved hairs. (Fiji Is) . . . . . Strumigenys scelesta

77
return to couplet #76
 * Dorsal alitrunk entirely smooth and shining, devoid of reticulate-punctate sculpture. (India) . . . . . Strumigenys smythiesii


 * Dorsal alitrunk partially to entirely reticulate-punctate . . . . . 78

78
return to couplet #77
 * In profile dorsum of promesonotum covered with a thick pelt of short curved ground pilosity, appearing weakly furry; in dorsal view sides of pronotum with a similar dense coat of short curved hairs, giving the sides a furry appearance. MI 45-48. (Sri Lanka, India, Malaysia (Sarawak, Sabah), Singapore, Indonesia (Sumatra, Krakatau, Java, Lombok, Seram, Flores, Sulawesi, Kai Besar, Aru, Tanimbar, Timor), Philippines (Mindanao, Luzon, Palawan), Papua New Guinea, Solomon Is, Vanuatu, Fiji Is, Samoa, Tonga, Marshall Is, Society Is, Caroline Is, Marquesas Is, Hawaii; also in Austral region) . . . . . Strumigenys godeffroyi


 * In profile dorsum of promesonotum with sparse scattered fine ground-pilosity, not appearing furry; in dorsal view sides of pronotum without a furry appearance. MI 38-41. (Thailand) . . . . . Strumigenys nytaxis

79
return to couplet #75
 * Dorsum of pronotum unsculptured, mostly or entirely smooth and shining when clean . . . . . 80


 * Dorsum of pronotum sculptured; usually reticulate-punctate, less commonly densely punctate, overlaid by fine rugulae, or predominantly rugulose . . . . . 82

80
return to couplet #79
 * Dorsal surface of propodeal tooth surmounted by a crest of spongiform tissue. Eye larger, with obviously more than 5 ommatidia in total; outer arc of eye visible in full-face view. Curved small hairs that fringe upper scrobe margin slender, narrowly spatulate . . . . . 81


 * Dorsal surface of propodeal tooth not surmounted b y a crest of spongiform tissue. Eye minute, with only 3-4 ommatidia in total; eye not visible in full-face view. Curved small hairs that fringe upper scrobe margin stout, spoon-shaped. (Bhutan) . . . . . Strumigenys uberyx

81
return to couplet #80
 * With head in profile the pair of standing hairs that straddle the midline near the occipital margin short, simple and stiff, straight or at most only shallowly curved; at highest point of vertex the head without a pair-of erect flagellate hairs. (Malaysia (West Malaysia, Sarawak, Sabah), Singapore, Indonesia (Sumatra, Java, Bali), Philippines (Palawan)) . . . . . Strumigenys juliae


 * With head in profile the pair of standing hairs that straddle the midline near the occipital margin disproportionately long, sub flagellate and strongly arched anteriorly; at highest point of vertex a pair of exceptionally long erect flagellate hairs present whose length is > ML. (Malaysia (Sarawak)) . . . . . Strumigenys eumekes

82
return to couplet #79
 * Ventral surface of petiole with a deep spongiform curtain or lobe, in profile its maximum depth equal to or greater than the height of the peduncle . . . . . 83

much less than the height of the peduncle. (Malaysia (West Malaysia), Indonesia (Sumatra)). . . . . Strumigenys leptodeira
 * Ventral surface of petiole with a narrow spongiform strip, in profile its maximum depth

83
return to couplet #82 short . . . . . 84
 * Pronotal humeral hair stiff, straight or only very shallowly evenly curved, relatively


 * Pronotal humeral hair flagellate, very long and slender . . . . . 86

84
return to couplet #83
 * Propodeal dorsum smooth and shining. Dorsum of petiolar peduncle and ascending (anterior) face of node margined on each side by a sharp cuticular carina; in dorsal view the carinae markedly concave through the zone where peduncle meets node, so that the pair of carinae are )(-shaped. Dorsum of petiole node unsculptured, as smooth as disc of postpetiole. (Fiji Is) . . . . . Strumigenys jepsoni


 * Propodeal dorsum mostly to entirely finely reticulate-punctate. Dorsum of petiolar peduncle and ascending (anterior) face of node not margined or at most with a low weak ridge on each side; if the latter then in dorsal view the carinae are parallel in the zone where peduncle meets node. Dorsum of petiole node finely reticulate-punctate, distinctly more coarsely sculptured than disc of postpetiole . . . . . 85

85
return to couplet #84
 * First gastral tergite with erect hairs restricted to two transverse rows, one basal and one apical, the sclerite between these without standing hairs; hairs of basal transverse row flagellate. Scape shorter, SI 85-86. (Taiwan) . . . . . Strumigenys hispida


 * First gastral tergite with erect hairs not restricted to two transverse rows, the sclerite between the basal and apical rows with standing hairs; hairs of basal transverse row stiff and simple. Scape longer, SI 98-100. (Japan, Taiwan) . . . . . Strumigenys solifontis

86
return to couplet #83
 * With head in full-face view a freely laterally projecting long flagellate hair present on dorsolateral margin at or very close to the occipital corner. Apicoscrobal hair also present, also long and flagellate, of the same form and length as the hair at the occipital corner . . . . . 87


 * With head in full-face view dorsolateral margin at occipital corner without a freely laterally projecting long flagellate hair (short simple or curved hairs may occur). Apicoscrobal hair present or absent, when present may be simple or flagellate but is always different in form and length from the hair at the occipital corner . . . . . 88

87
return to couplet #86
 * Cephalic ground-pilosity and pilosity that fringes upper scrobe margins simple and extremely fine. Hairs on leading edge of scape fine and simple. Head narrower and mandibles shorter, CI77, MI 34. (India) . . . . . Strumigenys habropilosa


 * Cephalic ground-pilosity and pilosity that fringes upper scrobe margins broadly spatulate. Hairs on leading edge of scape spatulate. Head broader and mandibles longer, CI 86, MI 39. (India) . . . . . Strumigenys hypoturba

88
return to couplet #86
 * With head in profile the pair of standing hairs that straddle the midline near the occipital margin disproportionately long, either flagellate or erect basally and with their apical sections abruptly angled or hooked anteriorly, or even looped . . . . . 89


 * With head in profile the pair of standing hairs that straddle the midline near the occipital margin short and stiff, straight to feebly curved and usually slightly inclined anteriorly; apical sections not abruptly angled or hooked anteriorly . . . . . 93

89
return to couplet #88
 * Dorsal margin of propodeal tooth surmounted by a shallow but conspicuous convex lobe or fringe of spongiform tissue throughout its length . . . . . 90


 * Dorsal margin of propodeal tooth free, not bearing a convex lobe or fringe of spongiform tissue . . . . . 92

90
return to couplet #89
 * Dorsal surface of petiole node and disc of postpetiole both smooth and shining, the two surfaces not contrasting. With petiole in dorsal view the node without a truncated anterior face, instead the lateral margins converging to a triangular anteromedian point. Scape relatively short, SI 74-77. (Japan, China, Taiwan) . . . . . Strumigenys minutula


 * Dorsal surface of petiole node sharply punctate or reticulate-punctate, disc of postpetiole smooth or with very scattered faint sculptural vestiges, the two surfaces contrasting. With petiole in dorsal view the node with a short truncated anterior face; lateral margins not converging to a triangular anteromedian point. Scape relatively long, SI 85 - > 100 . . . . . 91

91
return to couplet #90
 * Scape relatively very long, SI 105-107. Outer margin of mandible straight; inner at full closure becoming divergent proximal of preapical tooth. Head and mandibles longer and narrower, CI 63-65, MI 56-58. (Indonesia (Sumatra)) . . . . . Strumigenys chimaera


 * Scape relatively shorter, SI 85-93. Outer margin of mandible convex; inner margins at closure remaining evenly convergent to preapical tooth. Head and mandibles shorter and broader, CI 66-70, MI 38-45. (India, Bhutan, Thailand, China, Taiwan, Malaysia (West Malaysia, Sarawak, Sabah), Indonesia (Sumatra, Java, Bali, Lombok, Sulawesi)) . . . . . Strumigenys nanzanensis

92
return to couplet #89
 * Pronotal dorsum reticulate-punctate, without superimposed longitudinal fine costulate sculpture. Dorsum of petiole node reticulate-punctate. Lamella on propodeal declivity broad, engaging propodeal tooth to its apex. SI 74-81, CI 70-73. (Indonesia (Sulawesi)) . . . . . Strumigenys vassago


 * Pronotal dorsum weakly punctate and with superimposed longitudinal fine costulate sculpture. Dorsum of petiole node smooth. lamella on propodeal declivity narrower, apex of propodeal tooth freely projecting. SI 91, CI 65-66. Indonesia (Timor)) . . . . . Strumigenys berkalial

93
return to couplet #88
 * Scape relatively short, SI 72-75. Minute species, HL 0.43-0.48, HW 0.31-0.34, SL 0.25. With head in profile dorsal surface from level of eye to occipital margin with numerous erect short stiff straight hairs; hairs at occipital margin the same or only fractionally longer, not strongly differentiated . . . . . 94


 * Scape relatively long, SI 83-100. Larger species, HL 0.54-0.70, HW 0.37-0.48, SL-0.42. With head in profile dorsal surface from level of eye to occipital margin with reclinate to somewhat elevated ground-pilosity that may be straight or curved, but without erect stiff straight hairs; hairs at occipital margin usually distinctly differentiated . . . . . 95

94
return to couplet #93
 * Apicoscrobal hair present. With head in profile erect hairs near highest point of vertex longer than maximum diameter of eye. (Malaysia (West Malaysia), Indonesia (Sumatra, Java)) . . . . . Strumigenys datryx


 * Apicoscrobal hair absent. With head in profile erect hairs near highest point of vertex shorter than maximum diameter of eye. (Philippines (Luzo)) . . . . . Strumigenys tenitecta

95
return to couplet #93
 * Dorsum of hind femur with a number of short erect simple hairs, a long erect flagellate hair may also be present close to the base. Anterior and posterior surfaces of hind femur also with short erect simple hairs. With petiole in profile anteriormost point of lateral spongiform lobe falls far posterior of level of anterior (ascending) face of node. Scape relatively longer, SI 95-100 . . . . . 96


 * Dorsum of hind femur without short erect simple hairs but with two long erect flagellate hairs, one close to the base and the other more distal. Anterior and posterior surfaces of hind femur without short erect simple hairs. With petiole in profile anteriormost point of lateral spongiform lobe reaches or very nearly reaches level of anterior (ascending) face of node. Scape relatively shorter, SI 79-89 . . . . . 97

96
return to couplet #95
 * Basigastral costulae restricted to limbus, not extending onto first gastral tergite proper. Mesonotal dorsum with 1-2 pairs of erect fine simple to flagellate hairs. Occipital margin with 2-4 hairs that are very weakly differentiated from the ground-pilosity, about equal in length but of slightly different shape and slightly more elevated. (Taiwan) . . . . . Strumigenys trada


 * Basigastral costulae traverse limbus and extend for an equal distance onto first gastral tergite proper. Mesonotal dorsum with 4 or more pairs of stout stiff hairs. Occipital margin with 4 or more stiff hairs that are very strongly differentiated from the ground-pilosity, being much longer and suberect to erect. (Taiwan) . . . . . Strumigenys lichiaensis

97
return to couplet #95 vertex to occipital margin, are strongly curved basally so that most of the length of each hair is parallel to the cephalic outline or even curves down to the surface in its apical portion. Scape averaging slightly longer, SI 90-95. (India). . . . . Strumigenys peraucta
 * With head in profile the anteriorly-directed ground-pilosity hairs, from highest point of


 * With head in profile the anteriorly-directed ground-pilosity hairs, from highest point of vertex to occipital margin, are very feebly curved basally so that each hair is elevated and inclined upward away from the cephalic outline. Scape averaging slightly shorter, SI 79-89 . . . . . 98

98
return to couplet #97
 * Smaller species, HL 0.54-0.62, HW 0.37-0.43. With propodeum in profile the tooth strongly sclerotised and clearly visible within the lamella. (Malaysia (West Malaysia, Sarawak)) . . . . . Strumigenys geminata


 * Larger species, HL 0.65-0.70, HW 0.45-0.48. With propodeum in profile the tooth very feebly or not sclerotised, either faintly defined or mostly invisible within the lamella. (China, Taiwan, Japan, Russia (Kuril Is), introduced in Hawaii) . . . . . Strumigenys lewisi

99
return to couplet #57
 * Upper scrobe margin with a narrow and deep semicircular excavation just anterior to level of eye; ventrolateral margin of head interrupted immediately in front of eye by a deep, roughly semicircular indentation in the margin; these two impressions linked by a vertical groove up the side of the head. (Papua New Guinea) . . . . . Strumigenys odalatra


 * Upper scrobe margin continuous, without a semicircular excavation just anterior to level of eye; ventrolateral margin of head continuous to eye or with a preocular notch or impression, but without a vertical groove up the side of the head . . . . . 100

100
return to couplet #99
 * With head in full-face view the upper scrobe margin with two or more flagellate or filiform hairs that freely project laterally; at least with one in apicoscrobal position and another anterior to this (dorsolateral margin of occipital lobe posterior to apex of scrobe may have additional laterally projecting hairs) . . . . . 101


 * With head in full-face view the upper scrobe margin usually with a single hair that freely projects laterally, in apicoscrobal position; this hair may be flagellate, filiform, or short and stiff; rarely apicoscrobal hair absent (dorsolateral margin of occipital lobe posterior to apex of scrobe may have laterally projecting hairs) . . . . . 123

101
return to couplet #100
 * Entire dorsum of petiole node, and all of side of node, completely concealed by a thick uniform bonnet-like covering of fine dense spongiform tissue. Postpetiole almost entirely obscured by fine dense spongiform tissue, only a small anteromedian patch of the disc free of spongiform tissue. (Papua New Guinea) . . . . . Strumigenys lopotyle


 * Entire dorsum of petiole node visible, most of side of node visible, not entirely concealed by a bonnet of thick spongiform tissue. Postpetiolar disc visible, in dorsal view spongiform tissue confined to periphery of sclerite . . . . . 102

102
return to couplet #101
 * Disc of postpetiole blanketed with strong reticulate-punctate, costulate or rugulose sculpture; if sculpture somewhat fainter mediodorsally then either mesopleuron, or metapleuron plus side of propodeum, or both, are mostly or entirely sculptured . . . . . 103


 * Disc of postpetiole smooth to feebly superficially sculptured; if traces of superficial sculpture present on disc then either mesopleuron, or metapleuron plus side of propodeum, or both, are mostly to entirely glassy smooth . . . . . 114

103
return to couplet #102
 * Dorsal surface of occipital lobes depressed, flat or shallowly concave in profile or dorsal view and sharply marginate laterally. Scrobe obsolete behind level of eye. Ventrolateral margin of head with a distinct preocular impression. Preapical tooth of mandible very widely separated from apicodorsal tooth. Pronotum marginate laterally, dorsum and side covered with a dense pelt of short curved hairs. With petiole in profile the length of the lateral spongiform lobe at least equal to the exposed cuticle of the node. (Indonesia (Irian Jaya)) . . . . . Strumigenys domitia


 * Dorsal surface of occipital lobes not depressed, convex in profile or dorsal view and not marginate laterally. Scrobe extends posteriorly beyond level of eye. Ventrolateral margin of head without a preocular impression. Preapical tooth of mandible close to apicodorsal tooth. Pronotum not marginate laterally, without a dense pelt of short curved hairs. With petiole in profile the length of the lateral spongiform lobe less than the exposed cuticle of the node . . . . . 104

104
return to couplet #103
 * Mesonotum with a single pair of erect fine hairs . . . . . 105


 * Mesonotum with 3 or more pairs of erect fine hairs . . . . . 106

105
return to couplet #104
 * In dorsal view basigastral costulae much longer than disc of postpetiole. Mesopleuron entirely glassy smooth. Petiole node in dorsal view as long as broad or slightly longer than broad. (Indonesia (Seram)) . . . . . Strumigenys separa


 * In dorsal view basigastral costulae shorter than disc of postpetiole. Mesopleuron mostly to entirely punctulate. Petiole node in dorsal view broader than long. (Indonesia (Kai Besar), Papua New Guinea) . . . . . Strumigenys ligur

106
return to couplet #104
 * With head in profile standing hairs on dorsum not restricted to area close to occipital margin; standing hairs numerous between occipital row and highest point of vertex, and also present anterior to this (at least to level of eye, often to level of frontal lobes) . . . . . 107


 * With head in profile standing hairs on dorsum mostly or entirely restricted to area close to occipital margin; at most with 1-2 extra pairs present between occipital row and highest point of vertex but always absent anterior to this . . . . . 111

107
return to couplet #106
 * Mesopleuron, most of metapleuron and side of propodeum smooth and shining . . . . . 108


 * Mesopleuron, metapleuron and side of propodeum densely and coarsely sculptured . . . . . 109

108
return to couplet #107
 * Pronotal dorsum and mesonotum sharply densely punctate, the two not contrasting; propodeal dorsum sculptured. With petiole node in profile height of anterior face subequal to or greater than length of dorsum. Apical funicular segment moderately constricted basally. Smaller species with shorter scapes; HL 0.56, HW 0.39, SI 72. (Thailand) . . . . . Strumigenys benulia


 * Pronotal dorsum longitudinally rugulose, mesonotum reticulate-punctate, the two contrasting; propodeal dorsum mostly smooth. With petiole node in profile height of anterior face much less than length of dorsum. Apical funicular segment not constricted basally. Larger species with longer scapes; HL 0.72, HW 0.52, SI 85. (Fiji Is) . . . . . Strumigenys daithma

109
return to couplet #107
 * Head relatively short and broad, CI 78; scape relatively short, SI 65. (Malaysia (Sabah)) . . . . . Strumigenys lebratyx


 * Head relatively long and narrow, CI 65-67; scape relatively long, SI 83-87 . . . . . 110

110
return to couplet #110
 * With head in full-face view freely laterally projecting hairs are present on both the dorsolateral and ventrolateral margins; those on dorsolateral margin arise from sharply defined acute triangular tubercles. Longest standing hairs on cephalic dorsum arise from highest point of vertex. (Malaysia (Sarawak), Indonesia (Sumatra)) . . . . . Strumigenys macerina


 * With head in full-face view freely laterally projecting hairs are present on the dorsolateral margin only and do not arise from triangular tubercles. Longest standing hairs on cephalic dorsum arise from close to occipital margin. (Malaysia (Sarawak), Philippines (Luzon)) . . . . . Strumigenys mododonta

111
return to couplet #106
 * Mesopleuron mostly smooth and unsculptured, any punctate sculpture is confined to periphery of sclerite. In profile the anterior coxa with transverse costate sculpture . . . . . 112


 * Mesopleuron deeply punctate everywhere. In profile the anterior coxa without transverse costate sculpture . . . . . 113

112
return to couplet #111
 * A row of erect fine hairs present on both the dorsal and the ventral surface of the middle and hind femur. Hind femur relatively short, maximum length ca 0.54. Longest erect hairs on dorsal alitrunk and first gastral tergite distinctly flagellate. (Thailand) . . . . . Strumigenys paraposta


 * A row of erect fine hairs present only on the ventral surface of the middle and hind femur, absent from the dorsal surface. Hind femur relatively long, maximum length ca 0.68. Longest erect hairs on dorsal alitrunk and first gastral tergite simple and shallowly curved, not flagellate. (Malaysia (Sabah)) . . . . . Strumigenys pliocera

113
return to couplet #111
 * Preapical dentition of mandible a minute denticle; inner margins of mandibles touching just proximal of preapical denticle at full closure. Petiole node in profile with height of anterior face subequal to length of dorsum. Dorsal surface of hind femur without suberect fine hairs and without gland bulla visible in apical quarter. Head broader and scape shorter, CI 82-83, SI 63. (Thailand) . . . . . Strumigenys nothomopyx


 * Preapical dentition of mandible a small acutely triangular tooth; inner margins of mandibles widely separated just proximal of preapical tooth at full closure. Petiole node in profile with height of anterior face much less than length of long shallowly convex dorsum. Dorsal surface of hind femur with suberect fine hairs and with a small but conspicuous gland bulla visible in apical quarter. Head broader and scape shorter, CI 68-74, SI 71-77. (Malaysia (Sarawak, Sabah), Indonesia (Sumatra)) . . . . . Strumigenys natynion

114
return to couplet #102
 * With head in full-face view the upper scrobe margin with 5 or more flagellate or long fine filiform hairs that freely project laterally (dorsolateral margin of occipital lobe posterior to apex of scrobe may have additional laterally projecting hairs). (Malaysia (Sarawak)) . . . . . Strumigenys rhadina


 * With head in full-face view the upper scrobe margin with only two flagellate or long fine filiform hairs that freely project laterally; one in apicoscrobal position and another anterior to this (dorsolateral margin of occipital lobe posterior to apex of scrobe may have additional laterally projecting hairs) . . . . . 115

115
return to couplet #114
 * Anterior clypeal margin with a deep narrow median notch or impression that is narrowly U-shaped or V-shaped. Scape relatively long, SI > 80. Apical segment of funiculus long and narrow, spindle-shaped, basally tapering to a very narrow neck at its articulation with the preapical segment . . . . . 116


 * Anterior clypeal margin transverse or broadly evenly shallowly concave across its entire width, without a deep median notch. Scape relatively short, SI < 80. Apical segment of funiculus not long and narrow, not spindle-shaped, not or only moderately tapering basally to its articulation with the preapical segment . . . . . 122

116
return to couplet #115
 * Preapical tooth of mandible spiniform and shallowly curved, its length about one-third greater than the maximum width of the mandible. (China, Vietnam) . . . . . Strumigenys rallarhina


 * Preapical tooth of mandible varying from a denticle to a triangular tooth but not spiniform, the tooth shorter than the maximum width of the mandible, usually distinctly shorter . . . . . 117

117
return to couplet #116
 * Inner margin of mandible forming a more or less straight line from its base to the apex of the preapical tooth, or short preapical tooth strongly inclined toward mandibular apex. Proximal margin of preapical tooth a continuation of line of inner margin of mandible proximal to it, or at most only feebly diverging from it; preapical tooth small or scarcely more than a prominent angle and not directed medially. (China, Taiwan) . . . . . Strumigenys formosensis


 * Inner margin of mandible not forming a straight line from its base to the apex of the preapical tooth; preapical tooth not strongly inclined toward mandibular apex. Proximal margin of preapical tooth diverging strongly from line of inner margin of mandible proximal to it; preapical tooth directed medially or nearly so . . . . . 118

118
return to couplet #117
 * Species with very long narrow head and extremely elongated scape; HL 0.99-1.01, CI 44-48, SL 0.70, SI 146-159. (Malaysia (Sarawak); Indonesia (Sumatra)) . . . . . Strumigenys barylonga


 * Species with shorter and broader head and shorter scape; HL < 0.90, CI > 50, SL < 0.60, SI < 130 . . . . . 119

119
return to couplet #118
 * Preapical tooth very small, in full-face view its length one-quarter or less of the width of the mandible at the point where the tooth arises. (Burma, Thailand) . . . . . Strumigenys feae


 * Preapical tooth larger, in full-face view its length half or more of the width of the mandible at the point where the tooth arises . . . . . 120

120
return to couplet #119
 * Species combining longer narrower head with longer scape, CI 52-60, SI > 110. (Thailand, Malaysia (West Malaysia, Sabah), Singapore, Indonesia (Sumatra, Java, Bali)) . . . . . Strumigenys kraepelini


 * Species combining shorter broader head with shorter scape, CI > 60, SI < 105 (usually SI < 100) . . . . . 121

121
return to couplet #120
 * In full-face view outer margin of mandible straight from near clypeal margin to level of preapical tooth; inner margin between same points also straight or even slightly convex. Mandibles and scapes averaging slightly longer, MI 45-49, SI 97-104. (China, Japan) . . . . . Strumigenys stenorhina


 * In full-face view outer margin of mandible shallowly convex from near clypeal margin to level of preapical tooth; inner margin between same points usually shallowly concave, more rarely approximately straight. Mandibles and scapes averaging slightly shorter, MI 42-45, SI 93-96 (India, Nepal, Bhutan, Thailand, China, Japan, Wallis Is) . . . . . Strumigenys exilirhina

122
return to couplet #115
 * Larger species with longer mandibles, HL 0.70 or more, MI > 45. Preapical dentition of mandible represented only by a small denticle. Dorsum of head covered with small fine reticulate-rugulose enclosures whose bases are filled with fine dense reticulate-punctate sculpture. (Taiwan) . . . . . Strumigenys lacunosa


 * Smaller species with shorter mandibles, HL 0.43-0.48, MI 30-33. Preapical dentition of mandible represented by a strongly defined spiniform tooth. Dorsum of head covered with strong reticulate-punctate sculpture, without reticulate-rugulose enclosures. (Indonesia (Sulawesi)) . . . . . Strumigenys furfara

123
return to couplet #100
 * In full-face view anterior clypeal margin with a deep U-shaped or V-shaped median notch or indentation, margin not transverse nor very shallowly evenly concave from side to side. Ventrolateral margin of head with a preocular notch or impression . . . . . 124


 * In full-face view anterior clypeal margin transverse or very shallowly evenly concave from side to side, without a deep median notch or indentation. Ventrolateral margin of head continuous to eye, without a preocular notch or impression . . . . . 126

124
return to couplet #123
 * Disc of postpetiole mostly to entirely smooth and shining, without reticulate or reticulate-punctate sculpture, at most with a few very short longitudinal rugulae near anterior margin. (Papua New Guinea) . . . . . Strumigenys nysu


 * Disc of postpetiole mostly to entirely reticulate or reticulate-punctate, disc may also have longitudinal rugulae crossing part or most of its length . . . . . 125

125
return to couplet #124
 * Larger species with narrower head and longer scape; HL 0.69, CI 62, SI 102. (Indonesia (Irian Jaya)) . . . . . Strumigenys montu


 * Smaller species with broader head and shorter scape; HL 0.54-0.60, CI 65-70, SI 89-94. (Papua New Guinea; also in Australia) . . . . . Strumigenys racabura

126
return to couplet #123
 * Mesonotum with 3-4 pairs of erect fine hairs. Hairs arising all over first gastral tergite, not restricted to a single transverse row at the apex of the sclerite and another transverse row at its base. Petiole in profile long and low, the node with a very short anterior face or without a differentiated anterior face . . . . . 127


 * Mesonotum with 1 pair of erect fine hairs. Hairs on first gastral tergite restricted to a transverse row at the apex of the sclerite and another transverse row at its base. Petiole in profile nodiform, the node with a strongly differentiated anterior face . . . . . 128

127
return to couplet #126
 * Promesonotal dorsum longitudinally rugulose. Metapleuron and side of propodeum mostly to entirely sculptured. Dorsum of propodeum not rounding smoothly and evenly into declivity, the two surfaces separated by a transverse angle or weak carina between the propodeal teeth. Larger species with longer mandibles and shorter scapes, HL 0.80-0.86, MI 45-49, SI 73-76. (Thailand) . . . . . Strumigenys dipsas


 * Promesonotal dorsum reticulate-punctate. Metapleuron and side of propodeum entirely smooth. Dorsum of propodeum rounding smoothly and evenly into declivity, the two surfaces not separated by a transverse angle or carina between the propodeal teeth. Smaller species with shorter mandibles and longer scapes, HL 0.60, MI 37, SI 83. (Fiji Is) . . . . . Strumigenys ekasura

128
return to couplet #126
 * Apical (sixth) antennal segment strongly constricted basally and forming a very narrow articulation with preapical segment. Hairs on first and second gastral tergites long, fine and flagellate. Mandibles and scapes longer, MI 47-50, SI 77-82 . . . . . 129


 * Apical (sixth) antennal segment broad basally, broadly articulated with preapical segment. Hairs on first and second gastral tergites short, erect and simple. Mandibles and scapes shorter, MI 30-33, SI 55-59. (Indonesia (Sulawesi)) . . . . . Strumigenys dantalion

129
return to couplet #128
 * Dorsal (outer) surface of hind basitarsus with 1 erect long flagellate hair; hind tibia without a similar hair. With petiole in profile height of anterior face of node less than length of dorsum. Dorsum of petiole node and disc of postpetiole equally sharply and densely reticulate-punctate. Head and alitrunk yellowish brown, gaster darker. (Papua New Guinea) . . . . . Strumigenys paimon


 * Dorsal (outer) surface of hind basi tarsus with 2 erect long flagellate hairs; hind tibia with a single similar hair. With petiole in profile height of anterior face of node greater than length of dorsum. Dorsum of petiole node usually more sharply and densely sculptured than disc of postpetiole. Head, alitrunk and gaster dark brown to blackish brown. (Papua New Guinea, Solomon Is) . . . . . Strumigenys frivaldszkyi

130
return to couplet #54
 * Fully closed mandible in full-face view very broad proximally and strikingly tapered distally, not linear or curvilinear. Outer margin of mandible flared outwards or strongly convex prebasally, the mandible not straight, not evenly convex, not evenly bowed outwards. In ventral view outer margin of mandible distal of level of anterior clypeal margin abruptly changing direction . . . . . 131


 * Fully closed mandible in full-face view usually obviously linear or curvilinear, sometimes slightly increasing in width toward base, sometimes with a minute inflection immediately in front of the clypeal margin. Outer margin of mandible not flared outwards or strongly convex prebasally, mandible either straight, evenly convex or evenly bowed outwards. In ventral view outer margin of mandible forms a more or less continuous line that does not abruptly change direction distal of level of anterior clypeal margin . . . . . 140

131
return to couplet #130
 * Disc of postpetiole unsculptured, smooth and shining. Metapleuron and side of propodeum unsculptured; mesopleuron always smooth . . . . . 132


 * Disc of postpetiole sculptured, usually finely and densely reticulate-punctate. Metapleuron and side of propodeum always reticulate-punctate; mesopleuron usually also with the same sculpture . . . . . 139

132
return to couplet #131
 * Pronotal humeral hair absent . . . . . 133


 * Pronotal humeral hair present . . . . . 138