Colobopsis vitrea

Colobopsis vitrea is confined to the tropics and is often seen foraging on tree trunks and on the ground in rain forest. Smith (1860) reported it as "running in numbers up and down tree trunks, probably in search of Aphides". Viehmeyer (1916) noted that in Singapore, C. vitrea "nests in thin bamboo, in rotten wood and in hollow branches of Mangifera. Females frequently on the lamp. One such caught female had raised 6 sterile females in a plaster nest". W.C. Crawley collected specimens of C. vitrea from "a hole in a tree" near Darwin. Staff of the Quarantine Service, Department of Primary Industries, Queensland collected specimens of C. vitrea (vial Hy77) from a wooden window sill at Cairns, Queensland on 5 June 1970.

Identification
A member of the Camponotus macrocephalus species-group. This group has the following characters:


 * Fore femurs swollen, much greater in diameter than middle and hind femurs, generally more swollen than in most other Camponotus species.
 * Spines or bristles on the lower surfaces of the tibiae lacking, or at most, only one or two (most Camponotus species possess two rows of 5 to 10 spines).
 * Major workers and queens with the anterior of the head is truncated and flattened (phragmotic).
 * Major and minor workers present, but not intermediate-sized workers (worker caste dimorphic).

Within this group, this species can be diangosed as follows:

Whole ant clothed in plentiful long erect setae except absent on most of underside of head. In lateral view, metanotal groove is depressed, mesonotum and propodeum form high, arched convexities.

Distribution based on Regional Taxon Lists
Australasian Region: Australia. Indo-Australian Region: Borneo, Indonesia, Malaysia, New Guinea, Philippines. Oriental Region: India, Nicobar Island, Thailand. Palaearctic Region: China.

Castes

 * Major

Nomenclature

 * incursor. Formica incursor Smith, F. 1860b: 95 (w.) INDONESIA (Batjan I.). Junior synonym of vitrea: Donisthorpe, 1932c: 459.
 *  vitrea. Formica vitrea Smith, F. 1860b: 94 (w.) INDONESIA (Batjan I.). Emery, 1899c: 7 (l.); Viehmeyer, 1916a: 160 (s.q.m.); Karavaiev, 1933a: 319 (m.). Combination in Camponotus: Dalla Torre, 1893: 257; in C. (Colobopsis): Emery, 1893e: 225. Combination in Colobopsis: Ward, et al., 2016: 350. Senior synonym of siggii: Forel, 1895e: 455; of adlerzii: Forel, 1895e: 458; of incursor: Donisthorpe, 1932c: 459. Current subspecies: nominal plus angustulus, carinatus (unresolved junior homonym), latinotus (unresolved junior homonym), oebalis, praeluteus, praerufus, vittatulus. See also: McArthur & Shattuck, 2001: 41.
 * adlerzii. Prenolepis adlerzii Forel, 1886f: 209 (w.) AUSTRALIA. Junior synonym of vitrea: Forel, 1895e: 458.
 * siggii. Camponotus (Colobopsis) angustata var. siggii Forel, 1893b: 436 (s.w.) THAILAND. Junior synonym of vitrea: Forel, 1895e: 455.

Type Material


Formica incursor

Holotype worker in. Labelled “Bac. 52.”

Formica vitrea

Two worker syntypes in. Labelled “Bac. 13.”

Taxonomic Notes
McArthur & Shattuck (2001) made no attempt to determine the distribution of C. vitrea outside Australia. They were unable to examine type material of C. vitrea and the concept they accepted was based on Smith's original description.

McArthur (2012) treats the junior synonym C. siggii as a full species but without comment or justification. This change is not followed here.

Major worker
In lateral view. Dark red brown, limbs and funiculus lighter coloured, gaster darker. Head: Truncation rounded 135°; side glossy with sparse extremely short, adpressed setae, without erect setae; few long and short, erect setae on vertex and posterior head, absent on anterior head; underside of head without erect setae. Pronotum and mesonotum: Uniform semicircle scarcely marked by pro-mesonotal suture, plentiful long and short, erect setae and sparse flat-lying setae. Metanotum: Trough with distinct sloping sides; spiracle directed upward, aperture level with dorsum. Propodeum: Humped high, also forming semicircle, slightly flattened on top; angle near right angle, rounded; declivity straight above, concave below; ratio dorsum/declivity about 1.5; spiracle situated midway between coxa and dorsum, directed backward, surrounded by glossy surface with very sparse, short, fine setae. Node: Short longitudinally, few long setae, without pubescence, lower and upper halves of anterior face straight, separated by rounded 135° angle; summit sharp; posterior face mostly straight. Gaster: Glossy. Fore femur: Swollen. Mid tibia: With plentiful sub-erect setae, without bristles inside. In dorsal view. Head: Sides weakly convex, tapering to front; vertex straight; scape with plentiful distinct setae raised 45°; frontal carinae wider than half 1{W, more or less continuous with lateral margins of clypeus; frontal area elongated, diamond shaped, depressed; max HW at eye centre; five teeth. Clypeus slightly raised above cheeks and separated on sides by ridge; anterior third of clypeus, surrounding cheeks and mandibles form a truncated plane separated from surroundings by rounded angle without striations; sides of clypeus narrow, widest at truncation then tapering to front; glossy without pubescence, with one or two erect setae; without carina; anterior margin very narrow, projecting, convex. Front or rear view. Node: Summit straight sometimes widely indented, with plentiful, short, fine setae.

Minor worker
Lateral view. Dark red brown, limbs and funiculus lighter, Head: Side glossy with sparse, extremely short, adpressed setae; vertex with few long and short fine setae; underside of head without erect setae. Mesosoma: Similar to major worker except aperture of metanotal spiracle placed above dorsum. Node: Short longitudinally with few long setae, lacking pubescence; lower and upper halves of anterior face straight, separated by rounded 135° angle; summit sharp but not as sharp as major; posterior face mostly straight. Gaster: Slightly darker than head, glossy. Fore femur: Little lighter coloured than coxa, swollen. Mid tibia: Plentiful sub-erect, long, setae, lacking bristles on inside. Dorsal view. Head: Sides nearly straight, tapering to front; vertex convex, flattened at centre; scape with plentiful distinct setae raised 45'; frontal carinae wider than half HW; frontal area indistinct triangle; max HW at eye centre. Clypeus: Without truncation, finely punctate, anterior margin convex, projecting, very wide; sides of clypeus straight; glossy, without pubescence with few fine, erect setae; with indistinct carina. Front or rear view. Node: Summit wide, straight, with plentiful; short; fine setae, sometimes indented.

Measurements
HW 0.85-1.55 mm, ILL 0.85-1.55 mm, PW 0.60- 1.05 mm, HT 0.65-1.20 mm, CARW 0.45-0.85 mm, TL 0.80-0.95 mm.

Worker. Length 2 lines (= 4 mm). Jet black, smooth and shinning; head a little wider than the thorax; eyes ovate, placed rather high on the sides of the head; the antennae longer than the thorax, flagellum slightly thickened towards the apex; the mandibles pale rufo-testaceous. Thorax narrow, compressed behind and strangulated at the base of the metathorax; the scale of the abdomen compressed, quadrate and slightly notched above. Abdomen wider than the head, subglobose; the apical margins of the segments narrowly pale testaceous. Hab. Bachian. This species is found on trees, running in numbers up and down the trunks, probably in search of Aphides.