Mexalictus (Mexalictus) mexicanus Eickwort

DUMESH, SHEILA, 2013, <p> <strong> Revision of the rare Mesoamerican bee genus <em> Mexalictus </ em> (Hymenoptera: Halictidae) with the description of </ strong> <br /> <strong> 21 new species </ strong> </ p>, Zootaxa 3708 (1), pp. 1-80 : 42-45

Mexalictus (Mexalictus) mexicanus Eickwort

( Figs. 132–137 )

Mexalictus mexicanus Eickwort, 1978 , J. Kans. Ent. Soc. 51(4): 570-577. Female, male.

Holotype. Female. MEXICO, 16 Mi E Toluca, 31 July 1962, University of Kansas Mexico Expedition , 9500ft [ KUM].

Diagnosis. Both sexes of this species can be distinguished by the following combination: gena dull and strongly granular; metapostnotum and propodeum strongly granular, with fine dorsal striation; outer hind tibial spur coarsely serrate, with 8 blunt teeth apically. The male is distinguished by the following: gena wider than compound eye, posteriorly expanded; mandible slender and long, without a subapical tooth. The female is diagnosable by the strongly granular metapostnotum and propodeum; no other female has this character. The male of this species is similar to M. genalis and M. laurencei but can be separated by the entirely dull (shiny) and posteriorly curved (pointed) gena.

Redescription, Female: Body length 7.8–7.9mm, wing length 6.0– 6.2mm, head width 1.70–1.75mm, ITW 1.14mm. Head and mesosoma metallic dark green, pubescence pale, whitish. Head: slightly elongate, L:W = 1.04– 1.08:1; pubescence yellowish on head and vertex anteriorly, compound eyes bare. (1) Labrum and mandible: dark brown, basal area of mandible dark brown, mandible red apically; with subrectangular basal area, medial length equal to half of width, flattened basal elevation, raised apically, narrow triangular distal process. (2) Clypeus: shiny, nearly third apical surface dark purple-brown; slightly longer than supraclypeal area, extending about 0.95X length below lower eye margin, weakly convex in lateral view, protuberance about equal to supraclypeal area; punctures separated by 1pd basally, less dense apically. (3) Supraclypeal area: as wide as to slightly wider than long, largest width subequal to length from upper clypeal margin to lower margin of antennal sockets; weakly granular, slightly shiny centrally becoming dulled between antennal sockets; convex, slightly protuberant, punctation evenly distributed, slightly sparser medioapically. (4) Lower paraocular area: dull above and towards supraclypeal area, shiny apically and laterally along inner margin of compound eye; punctures separated by 1pd, sparser toward supraclypeal area (2pd), becoming finely punctate apically and nearly impunctate towards paraocular lobe. (5) Frontal area: frontal line carinate between antennae, slightly distinct above antennal sockets, with visible line continuing up to medial ocellus, shiny impunctate triangle nearly absent; compound eye more convex below than above; punctation coarse and crowded above antennae. (6) Vertexal area: shiny, with weak transverse depression; IOD = 2MOD, OOD = 1.6MOD, OVD = 1.2MOD; larger punctures separated by 2pd, smaller punctures closely spaced; punctuation more dense near eyes. (7) Genal and hypostomal areas: genal area shiny, hypostomal area dulled; genal area subequal to compound eye in lateral view; punctures separated by 1–3pd, somewhat denser near outer margin of compound eye. (8) Antenna: dark brown, flagellum weakly reddish ventrally, scape, pedicel, and F1–F3 appearing darker than F4–F10; scape reaching posterior median ocellus, pedicel slightly longer than wide, F2 and F3 subequal in size, both wider than long and shorter than F1, flagellomeres slightly increasing in length distally, F10 longer than wide. Mesosoma: metallic reflections absent, (9) Pronotum: smooth, nearly impunctate, shiny; posterodorsal margin of pronotum with complete band of hairs, including pronotal lobe which is densely outlined. (10) Mesoscutum: weakly dulled throughout; densely and slightly coarsely punctate along margins and admedian line; punctures of 2 sizes, larger punctures deep, separated by 2–4pd, smaller punctures shallow and more dense, mostly on lateral and apical surfaces of mesoscutum. (11) Mesoscutellum: basally shiny with apical dulled; punctation similar to those of mesoscutum, large punctures very sparse, small punctures most dense apically and along medial line; with a medial carinate line raised, extending to apical. (12) Metanotum: entirely dulled, with sparse punctures similar in diameter to those of mesoscutum and mesoscutellum. (13) Mesopleuron: obscurely punctate, not shiny or very weakly shiny, granular, with punctuation sparse to absent; hypoepimeral area and central episternum mostly impunctate, smooth. (14) Metapleuron: transversely striate basally, otherwise weakly granular and somewhat shiny. (15) Metapostnotum and propodeum: length of metapostnotum slightly longer than apical width, apically angulate, dorsally bare, strongly granular basally, with fine longitudinal striation extending farther basally, weak or absent medially; propodeum laterally and posteriorly granular, weakly shiny. (16) Wings: clear, veins and stigma brown, membrane slightly infuscate; first recurrent vein meeting at or 1 vein width basad of second transcubital vein; second submarginal cell with anterior margin length of posterior margin. (17) Tegula: dark brown; punctate anteriorly, with few long branched hairs distally, posteriorly transparent, with hyaline, dull anterior margin. (18) Foreleg: dark brown; hairs pale golden on tarsi, metafemoral brush and anterior tibia; coxa, trochanter, and femur with branching shorter erect hairs; pubescence on tibia and basitarsus dense, hairs long, not branched. (19) Middle leg: as foreleg, hairs brownish on outer surfaces of tibia and basitarsus as well as basitibial plate; tibia with lateral patch of pale, long and dense pubescence on apical 2/3. (20) Hind leg: as middle leg, coxa and trochanter with long, branching, pale pubescence; femoral scopa well formed with long branching hairs; tibia densely pubescent, hairs long and erect; basitarsus with several branched hairs, pubescence less dense than on tibia; femur 3X as long as greatest width; tibia 4X as long as greatest width; basitarsus 3.5X as long as greatest width; tibial spurs translucent yellow, apically darkened; inner hind tibial spur curved, rather coarsely serrate with 8 blunt teeth apically, laterally darkened; outer hind tibial spur weakly curved at apical 1/3. Metasoma: reflections on metasomal terga weak to absent. (21) Terga: entirely shiny, nearly uniform in colour; metallic reflections absent; T1 entirely shiny and polished, nearly impunctate, T2–T4 with punctures separated by 2–3pd basally, becoming deeper and more sparse apically (>5pd), apical margins nearly impunctate, T5 with sparse and deeper punctures, separated by 4–6pd; pubescence pale on T1–T3 with short and thin hairs sparsely distributed throughout tergum and few dark hairs scattered laterally, pubescence dark and long on T4–T5, more dense than on T1–T3. (22) Sterna: ventral hairs long, plumose and pale on S1 near crossing with mesosoma, becoming brownish S5–S6.

Male: Body length 5.5–6.5mm, wing length 5.5–5.7mm, head width 1.60–1.64mm, ITW 0.95mm. Head and mesosoma dark green, pubescence on yellowish–white. Head: round, L:W = 1.02–1.03:1. (1) Labrum and mandible: basally, about 2.6 X as wide as long; rounded, smooth elevation extending length and width, medially flattened, may appear slightly depressed; distal process extending beyond basal area for up to 0.5X length of labrum; mandible dark brown, elongate, without subapical tooth, reaching beyond outer eye angle when closed. (2) Clypeus: nearly entirely metallic, apical margin brown; slightly wider than long, apically depressed; punctures separated by <2pd basally, becoming sparser laterally and apically, especially in depressed area. (3) Supraclypeal area: protuberant, slightly longer than apical width; punctures separated by <2pd laterally, becoming sparse medially. (5) Frontal area: frontal line not carinate above antennal sockets. (6) Vertexal area: IOD = 1.8MOD, OOD = 1.7MOD, OVD = 1MOD; larger punctures separated by 2pd, smaller punctures closely spaced; punctuation more dense near eyes. (7) Genal and hypostomal areas: genal area slightly wider than eye in lateral view, posteriorly expanded broadly, nearly at a right angle, ventrally sharply angled; hypostomal area posteriorly striate. (8) Antenna: reaching basal mesoscutellum; scape reaching median anterior ocellus; pedicel about as long as wide; F1 slightly longer than pedicel, about as long as wide, longer than F2, subequal in size to F3–F10. Metasoma (21) Terga: metallic reflections absent; pygidial plate broadly rounded with elevated rim, depressed centrally, shiny and smooth, or with irregular rough areas. (22) Sterna: S4–S6 with graduli distant from antecostae, at about a right angle; S4 with long plumose hairs medially directed on concave apico-median area; S5 broadly concave centrally, medial plumose hairs longest apically, projecting ventrally as apical tuft; S6 with plumose hairs medially directed. (23) Terminalia: see Figs. 136, 137 .

Material examined. MEXICO, Mexico, 15.5m E Toluca, 6 July 1961, 9500’, U. Kans. Mex. Exped. ( University of Kansas Mexico Expedition) ; Distrito Federal, Desierto de los Leones, X. 13.62, H. & M. Townes ; Morelos, Huitzilac, Derrame del Chichinautzin , km 85.5, 04/05/1996, 11:20H 2475m 1901’26N 9909’07W; same locality, 01/12/1996, 10:30H; same locality, km 85, 15/10/1995, 10:35H 2500m 1901’31N 9909’22W; same locality, km 85.5, 28/08/1996, 12:55H 2520m 1901’34N 9909’39W; same locality, km 86.6, 16/08/1997, 13:30H 2450m 1901’33N 9908’ 36W.

Figures

FIGURES 132–137. Mexalictus mexicanus Eickwort (1978), 132. Female lateral habitus, 133. Female head, 134. Male lateral habitus, 135. Male head, 136. Male genital capsule, dorsal view, 137. Male genital capsule, ventral view. Scale bars = 1mm.