Myrmecocystus flaviceps

Distribution
This taxon was described from U.S.A.

Nomenclature

 *  flaviceps. Myrmecocystus yuma var. flaviceps Wheeler, W.M. 1912d: 177 (w.) U.S.A. Snelling, R.R. 1976: 84 (q.m.). Raised to species: Creighton, 1950a: 443.

Worker
Snelling (1976) - Measurements. HL 0.83-1.23 (0.95); HW 0.73-1.23 (0.87); SL 0.97-1.43 (1.07); WL 1.23-1.80 (1.27); PW 0.53-0.87 (0.57).

Head: Longer than broad in small workers to slightly broader than long in largest, CI 87-103 (91), over 90 in more than 80% of samples; HL less than SL, SI 108-129 (123); in frontal view broadest at or below lower eye margin, sides straight or barely convex, little or not at all convergent toward mandibular insertion. Occiput, in frontal view, evenly rounded from side to side, without lateral corners. Eye small, 0.75-0.83 (0.75) x first flagellomere; OMD 1.38-1.88 (1.63) x EL. Mandible usually with seven teeth, range: 6-8.

Thorax: Slender to moderately stout, PW 0.41-0.49 (0.45) x WL; mesonotum evenly sloping to metanotum. Propodeum higher than long; in profile, juncture of basal and posterior faces broadly rounded.

Petiole: In profile, bluntly cuneate, summit broadly rounded; crest, from behind, fiat or slightly convex, without median notch.

Vestiture: Cephalic pubescence dilute, producing weak sheen on malar area and frons, more pronounced on occiput; pubescence moderately dense on thorax; denser on first three terga.

Malar area, in frontal view, with twelve or fewer fine, erect hairs; longest occipital hairs about 0.5 x MOD; pronotal disc with 10-14 short, erect hairs, longest 0.5, or less, x MOD; mesonotum with about 12 short, erect hairs dorsally, longest less than 0.5 x MOD; propodeum with about an equal number on basal face; crest and sides of petiole with a few very short, erect hairs. First three terga with sparse discal hairs which are shorter than apical width of hind tibia, hairs longer on apical margins, succeeding segments and on sterna. Short, erect to subdecumbent hairs numerous on anterior and lateral surfaces of scape, all femora (except inner face of fore femur) and extensor surface of tibiae.

Integument: Head lightly shagreened and shiny, with close micropunctures on frons and frontal lobe; coarser and sparser on occiput. Thoracic dorsum moderately shiny, slightly and closely shagreened, sides and propodeum duller. First three terga slightly shiny, closely shagreened and micropunctate.

Color: Normal: Head, thorax and appendages yellowish-ferruginous, head a little darker on frons and occiput; gaster light to medium brownish. Baja California: Frons, occiput, thorax and gaster dark brownish; clypeus, mandible and malar area yellowish; legs medium brownish.

Queen
Snelling (1976) - Measurements. HL 1.47-1.63; HW 1.57-1.73; SL 1.37-1.53; WL 3.4-3.8; PW 1.9-2.5.

Head: Slightly to distinctly broader than long, CI 102-111, longer than to as long as scape, SI 90-100; malar area, in frontal view, barely convex, not notably convergent toward mandibular insertion. Occiput, in frontal view, gently convex, lateral corners broadly rounded. Eye small, 1.00-1.45 x first flagellomere; OMD 1.46-1.73 x EL. OOD 4.00-4.34 x OD; IOD 2.66-3.33 x OD. Mandible with seven to nine, usually eight, teeth. Penultimate segment of maxillary palp approximately parallel-sided, not notably narrowed at base or apex.

Thorax: Robust, PW 0.53-0.69 x WL. Posterior half of mesoscutum, scutellum and metanotum flattened, in profile, forming a continuous slope to base of propodeum. Propodeum, in profile, usually evenly, gently convex, without defined basal and posterior faces; rarely with basal and posterior faces distinct.

Petiole: Sharply cuneate in profile, summit narrow; in frontal view, crest weakly to strongly angularly incised.

Vestiture: Cephalic pubescence moderately dense on occiput, lighter on frontal lobes and malar area, sparse elsewhere. Thoracic pubescence sparse on mesoscutum and scutellum, dense elsewhere. Gastric pubescence moderately dense basally and on sides of terga, but with broad median areas of first four segments very sparsely pubescent.

Side of head, in frontal view, with six or more long, slender flexuous hairs; occipital hairs erect, slender, longest less than MOD. Mesoscutum with sparse erect hairs, longest less than MOD; scutellum with sparse erect hairs, some of which are about equal to EL; pleura with scattered erect hairs similar to those of scutum. Propodeum with scattered erect hairs on all surfaces, longest less than MOD. Petiole with short erect hairs on sides and crest. Terga with sparse, short erect hairs, those of margins not conspicuously longer than those of discs; hairs of fifth tergum longer than those of first four segments. Scape with scattered short, suberect hairs on all except inner face and abundant shorter subdecumbent hairs. Fore femur with abundant long, erect hairs on ventral and outer faces, none on inner and dorsal faces; mid and hind femora and all tibiae with abundant short subdecumbent to erect hairs. Hind wing with fringe hairs along posterior margin.

Integument: Cephalic surfaces shiny; sides of clypeus irregularly, lightly shagreened and with scattered coarse punctures; malar area with abundant, fine, often elongate, punctures of variable size; frontal lobes with punctures irregularly spaced, often with impunctate areas, punctures of two sizes; frons with extensive impunctate areas on either side of midline, otherwise with sparse, fine punctures; occiput closely, finely micropunctate and with scattered coarser punctures. Scutum shiny, with scattered coarse punctures, sparser in middle; parapsis with punctures irregularly spaced and of two sizes. Median area of scutellum sparsely punctate, marginal areas more finely and closely punctate. Pleura slightly shiny, anepisternum a little more coarsely and less closely punctate than katepisternum. Propodeum dull, closely shagreened. Four basal terga moderately shiny on discs, lightly shagreened and with only sparse setigerous punctures.

Color: Head dark ferruginous with infuscated occipital and frontal areas; thorax dark brownish; gaster dark brown to blackish, with margins of segments yellowish; appendages medium brownish. Wings whitish, veins and stigma yellowish to brownish yellow.

Male
Snelling (1976) - Measurements. HL 0.68-0.80; HW 0.70-0.80; SL 0.77-0.93; PW 0.77-1.10; WL 1.50-1.90.

Head: Longer than broad to slightly broader than long, CI 96-102; distinctly shorter than scape, SI 108-123; in frontal view, malar margins straight, distinctly convergent toward mandibular insertions; occipital margin evenly convex, without defined lateral angles. OMD 0.67-1.00 x EL; 000 2.50-3.50 x OD; IOD 3.00-3.50 x OD. Mandible without preapical notch, cutting margin edentate.

Thorax: Moderately robust to robust, PW 0.51-0.64 x WL. Propodeum without clearly defined basal face.

Petiole: Thick in profile, bluntly cuneate; crest, in frontal view, narrowly, shallowly, angularly incised.

Vestiture: Pubescence sparse on head and thorax, denser on propodeum; very scattered on first tergum, more conspicuous, but still sparse, on next three segments.

Cephalic pilosity fairly abundant, usually with about six hairs in malar area in frontal view; occipital hairs fine, longest less than half MOD. Mesoscutal hairs sparse, longest less than 0.5 x MOD; scutellar hairs sparse, longest a little less than MOD; pleural hairs sparse, none longer than 0.5 x MOD; propodeum with scattered hairs on side and across base, longest about 0.5 x MOD. Petiole with sparse short hairs on side and crest. Gaster with sparse, long, slender hairs, longest not exceeding MOD. Scape with abundant suberect to erect hairs, much sparser, or absent, from posterior face. Femora with suberect to erect hairs on all surfaces; tibiae with short, sparse, suberect hairs on extensor surface, finer, shorter, subdecumbent hairs elsewhere. Posterior margin of hind wing with fringe hairs.

Integument: Head moderately shiny, lightly shagreened, nearly smooth on vertex; with scattered fine setigerous punctures. Discs of scutum and scutellum shiny, lightly shagreened, usually with polished median areas of irregular extent, and with scattered setigerous punctures; pleura slightly shiny, closely shagreened and with sparse setigerous punctures. Middle of propodeum smooth and shiny, segment otherwise closely shagreened and slightly shiny. Gastric segments moderately shiny, lightly shagreened, median areas of terga one to three often subpolished.

Color: Medium to dark brownish, gaster sometimes more yellowish (callows?); flagellum, mandibles and legs lighter. Wings whitish, veins and stigma yellowish to brownish yellow.