A new species, Lasioglossum (Eickwortia) hienae, from Mexico (Apoidea: Halictidae)

A new species from Colima, Mexico, Lasioglossum (Eickwortia) hienae Gibbs & Dumesh, new species, is described and illustrated.  Lasioglossum hienae is distinguished from related species based on a combination of morphological, geographical, and molecular evidence.  A species distribution model is used to predict the potential distribution of the known species of L. (Eickwortia).  An identification key is provided

Diagrammatic calculation of energy spectrum of quantum impurity in degenerate Bose-Einstein condensate

In this paper we considered a quantum particle moving through delute Bose-Einstein condensate at zero temperature. In our formulation the impurity particle interacts with the gas of uncoupled Bogoliubov's excitations. We constructed the perturbation theory for the Green's function of the impurity particle with respect to the impurity-condensate interaction employing the coherent-state path integral approach. The perturbative expansion for the Green's function is resumed into the expansion for its poles with the help of the diagrammatic technique developed in this work. The dispersion relation for the impurity clothed by condensate excitations is obtained and effective mass is evaluated beyond the Golden rule approximation

An application for ESR measurements using an Orotron as the millimeter wave radiation source

The microwave tube Orotron (OR-290/1) was developed as millimeter-wave radiation source in Institute of Applied Physics, Russian Academy of Sciences. The output power and frequency were measured. The electron spin resonance (ESR) spectrometer was developed by using an orotron as moderate power millimeter-wave radiation source. The ESR spectrum of DPPH, which was used for standard sample, were successfully measured by this spectrometer.research repor

Higher energy states in the CO dimer: Millimeter-wave spectra and rovibrational calculations

Contains fulltext : 34677.pdf (publisher's version ) (Open Access)New extensive millimeter-wave measurements of the (CO)-C-12-O-16 dimer have been made, and more than 300 new spectral transitions have been observed in the frequency range 81-135 GHz. A joint analysis of these and previous millimeter-wave data yielded the precise location of 33 new energy levels of A(+) symmetry and 20 levels of A(-) symmetry. These energy levels are located at 8-18 cm(-1) above the zero-point level. Some of them belong to already known stacks, and others make up 9 new stacks of the dimer. Newly determined stacks have K = 0, 1, and, for the first time, 2, where K is the projection of the total angular momentum on the intermolecular axis. The energy levels from accompanying rovibrational calculations with the use of a recently developed hybrid CCSD(T)/DFT-SAPT potential are in very good agreement with experiment. Analysis of the calculated wave functions revealed that two new stacks of A(+) symmetry with K = 2 correspond to overall rotation of the dimer while the other newly observed stacks belong to the geared bend overtone modes. The ground vibrational states of the two "isomers" found are more or less localized at the two minima in the potential surface, whereas all the geared bend excited states show a considerable amount of delocalization

FIGURE 1 in <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>

FIGURE 1. Distribution map of Mexalictus (Mexalictus s. str. in red circles, M. (Georgealictus) in black circles).Published as part of &lt;i&gt;DUMESH, SHEILA, 2013, &lt;p&gt;&lt;strong&gt;Revision of the rare Mesoamerican bee genus &lt;em&gt;Mexalictus&lt;/em&gt; (Hymenoptera: Halictidae) with the description of &lt;/strong&gt;&lt;br&gt;&lt;strong&gt;21 new species&lt;/strong&gt;&lt;/p&gt;, pp. 1-80 in Zootaxa 3708 (1)&lt;/i&gt; on page 5, DOI: 10.11646/zootaxa.3708.1.1, &lt;a href="http://zenodo.org/record/10099252"&gt;http://zenodo.org/record/10099252&lt;/a&gt

Mexalictus (Mexalictus) mexicanus Eickwort

&lt;i&gt;Mexalictus (Mexalictus) mexicanus&lt;/i&gt; Eickwort &lt;p&gt;(Figs. 132&ndash;137)&lt;/p&gt; &lt;p&gt; &lt;i&gt;Mexalictus mexicanus&lt;/i&gt; Eickwort, 1978, J. Kans. Ent. Soc. 51(4): 570-577. Female, male.&lt;/p&gt; &lt;p&gt; &lt;b&gt;Holotype.&lt;/b&gt; Female. MEXICO, 16 Mi E Toluca, 31 July 1962, University of Kansas Mexico Expedition, 9500ft [KUM].&lt;/p&gt; &lt;p&gt; &lt;b&gt;Diagnosis.&lt;/b&gt; 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 &lt;i&gt;M. genalis&lt;/i&gt; and &lt;i&gt;M. laurencei&lt;/i&gt; but can be separated by the entirely dull (shiny) and posteriorly curved (pointed) gena.&lt;/p&gt; &lt;p&gt; &lt;b&gt;Redescription,&lt;/b&gt; &lt;i&gt;Female:&lt;/i&gt; Body length &lt;b&gt;7.8&ndash;7.9mm&lt;/b&gt;, wing length &lt;b&gt;6.0&ndash; 6.2mm&lt;/b&gt;, head width &lt;b&gt;1.70&ndash;1.75mm&lt;/b&gt;, ITW &lt;b&gt;1.14mm&lt;/b&gt;. Head and mesosoma metallic dark green, pubescence pale, whitish. &lt;i&gt;Head:&lt;/i&gt; slightly elongate, L:W = 1.04&ndash; 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&ndash;3pd, somewhat denser near outer margin of compound eye. (8) Antenna: dark brown, flagellum weakly reddish ventrally, scape, pedicel, and F1&ndash;F3 appearing darker than F4&ndash;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. &lt;i&gt;Mesosoma:&lt;/i&gt; 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&ndash;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. &lt;i&gt;Metasoma:&lt;/i&gt; 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&ndash;T4 with punctures separated by 2&ndash;3pd basally, becoming deeper and more sparse apically (&gt;5pd), apical margins nearly impunctate, T5 with sparse and deeper punctures, separated by 4&ndash;6pd; pubescence pale on T1&ndash;T3 with short and thin hairs sparsely distributed throughout tergum and few dark hairs scattered laterally, pubescence dark and long on T4&ndash;T5, more dense than on T1&ndash;T3. (22) Sterna: ventral hairs long, plumose and pale on S1 near crossing with mesosoma, becoming brownish S5&ndash;S6.&lt;/p&gt; &lt;p&gt; &lt;i&gt;Male:&lt;/i&gt; Body length &lt;b&gt;5.5&ndash;6.5mm&lt;/b&gt;, wing length &lt;b&gt;5.5&ndash;5.7mm&lt;/b&gt;, head width &lt;b&gt;1.60&ndash;1.64mm&lt;/b&gt;, ITW &lt;b&gt;0.95mm&lt;/b&gt;. Head and mesosoma dark green, pubescence on yellowish&ndash;white. &lt;i&gt;Head:&lt;/i&gt; round, L:W = 1.02&ndash;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 &lt;2pd basally, becoming sparser laterally and apically, especially in depressed area. (3) Supraclypeal area: protuberant, slightly longer than apical width; punctures separated by &lt;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&ndash;F10. &lt;i&gt;Metasoma&lt;/i&gt; (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&ndash;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.&lt;/p&gt; &lt;p&gt; &lt;b&gt;Material examined.&lt;/b&gt; MEXICO, Mexico, 15.5m E Toluca, 6 July 1961, 9500&rsquo;, U. Kans. Mex. Exped. (University of Kansas Mexico Expedition); Distrito Federal, Desierto de los Leones, X. 13.62, H. &amp; M. Townes; Morelos, Huitzilac, Derrame del Chichinautzin, km 85.5, 04/05/1996, 11:20H 2475m 1901&rsquo;26N 9909&rsquo;07W; same locality, 01/12/1996, 10:30H; same locality, km 85, 15/10/1995, 10:35H 2500m 1901&rsquo;31N 9909&rsquo;22W; same locality, km 85.5, 28/08/1996, 12:55H 2520m 1901&rsquo;34N 9909&rsquo;39W; same locality, km 86.6, 16/08/1997, 13:30H 2450m 1901&rsquo;33N 9908&rsquo; 36W.&lt;/p&gt;Published as part of &lt;i&gt;DUMESH, SHEILA, 2013, &lt;/i&gt;&lt;p&gt;&lt;i&gt; &lt;strong&gt; Revision of the rare Mesoamerican bee genus &lt;em&gt; Mexalictus (Hymenoptera: Halictidae) with the description of &lt;br&gt; &lt;strong&gt; 21 new species , pp. 1-80 in Zootaxa 3708 (1)&lt;/strong&gt;&lt;/em&gt;&lt;/strong&gt;&lt;/i&gt;&lt;strong&gt;&lt;em&gt;&lt;strong&gt; on pages 42-45, DOI: 10.11646/zootaxa.3708.1.1, &lt;a href="http://zenodo.org/record/10099252"&gt;http://zenodo.org/record/10099252&lt;/a&gt;&lt;/strong&gt;&lt;/em&gt;&lt;/strong&gt;&lt;/p&gt

FIGURES 182–183. Mexalictus veracruzense Dumesh, n in <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>

FIGURES 182–183. Mexalictus veracruzense Dumesh, n. sp., 182. Female lateral habitus, 183. Female head. Scale bars = 1mm.Published as part of &lt;i&gt;DUMESH, SHEILA, 2013, &lt;p&gt;&lt;strong&gt;Revision of the rare Mesoamerican bee genus &lt;em&gt;Mexalictus&lt;/em&gt; (Hymenoptera: Halictidae) with the description of &lt;/strong&gt;&lt;br&gt;&lt;strong&gt;21 new species&lt;/strong&gt;&lt;/p&gt;, pp. 1-80 in Zootaxa 3708 (1)&lt;/i&gt; on page 75, DOI: 10.11646/zootaxa.3708.1.1, &lt;a href="http://zenodo.org/record/10099252"&gt;http://zenodo.org/record/10099252&lt;/a&gt

FIGURES 37–40. 37. Mexalictus albofasciatus Dumesh, n in <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>

FIGURES 37–40. 37. Mexalictus albofasciatus Dumesh, n. sp. female metasoma, apical margins with fasciae, 38. M. anatolii Dumesh, n. sp. female metasoma, apical margins hyaline, 39. M. anatolii female head and mesosoma (lateral view), green, 40. M. jovelus Dumesh, n. sp. female head and mesosoma (lateral view), brown-black. Scale bars = 1mm.Published as part of &lt;i&gt;DUMESH, SHEILA, 2013, &lt;p&gt;&lt;strong&gt;Revision of the rare Mesoamerican bee genus &lt;em&gt;Mexalictus&lt;/em&gt; (Hymenoptera: Halictidae) with the description of &lt;/strong&gt;&lt;br&gt;&lt;strong&gt;21 new species&lt;/strong&gt;&lt;/p&gt;, pp. 1-80 in Zootaxa 3708 (1)&lt;/i&gt; on page 13, DOI: 10.11646/zootaxa.3708.1.1, &lt;a href="http://zenodo.org/record/10099252"&gt;http://zenodo.org/record/10099252&lt;/a&gt

Mexalictus (Mexalictus) astriatus Dumesh 2013, new species

&lt;i&gt;Mexalictus (Mexalictus) astriatus&lt;/i&gt; Dumesh, new species &lt;p&gt;(Figs. 94&ndash;99)&lt;/p&gt; &lt;p&gt; &lt;b&gt;Holotype.&lt;/b&gt; Female. MEXICO, Mexico, 16 mi. E Toluca, 9500&rsquo;, 31 July 1962, University of Kansas Mexico Expedition [KUM].&lt;/p&gt; &lt;p&gt; &lt;b&gt;Diagnosis.&lt;/b&gt; Both sexes of this species can be distinguished by their metapostnotal sculpture which lacks striae, all other species have striae at least basally on the metapostnotum. In addition, the following combination: supraclypeal area impunctate on disc; apical dark region of clypeus triangular; first recurrent vein entering second submarginal cell 1/3 cell length from apex. This species is most similar to &lt;i&gt;M. micheneri&lt;/i&gt; with which it shares the elongate head, but can be differentiated by the non-striate dorsal metapostnotum. It is slightly larger in size than most other members of this subgenus.&lt;/p&gt; &lt;p&gt; &lt;b&gt;Description.&lt;/b&gt; &lt;i&gt;Female (Holotype):&lt;/i&gt; Body length &lt;b&gt;8.8mm&lt;/b&gt;, forewing length &lt;b&gt;6.0&ndash; 6.3mm&lt;/b&gt;, head width &lt;b&gt;1.72&ndash; 1.75mm&lt;/b&gt;, ITW &lt;b&gt;1.28&ndash;1.33mm&lt;/b&gt;. Head and mesosoma metallic greenish blue, pubescence pale whitish. &lt;i&gt;Head&lt;/i&gt;: slightly longer than wide, L:W = 1.15&ndash;1.18:1. (1) Labrum and mandible: labrum dark brown with subrectangular basal area, medial length equal to half of width, basal elevation flattened, apicomedial area elevated, distal process narrow triangular; mandible basally dark brown becoming apically red, with distinct subapical tooth. (2) Clypeus: shiny, nearly half apical surface dark purple-brown; length subequal to length of supraclypeal area, 0.8 of length below lower ocular tangent, weakly convex in lateral view, slightly protuberant; punctures of 2 sizes basally, smaller punctures separated by &lt;1pd, larger punctures separated by &lt;2pd; punctures coarser and sparser apically, separated by&gt;2pd; with subapical row of dark bristles. (3) Supraclypeal area shiny, convex, more protuberant than clypeus; length subequal to clypeal length; greatest width subequal to length from upper clypeal margin to lower margin of antennal sockets; punctation absent apicomedially (apical 2/3 impunctate medially), lateral areas with punctures separated by 1&ndash;2pd; punctures smaller and more dense and surface slightly dull below antennal sockets. (4) Lower paraocular area: shiny, becoming dull towards antennal socket; punctures separated by &lt;1pd, becoming slightly sparser lateral to supraclypeal area, punctures fine and well separated towards paraocular lobe; paraocular lobe black and nearly impunctate. (5) Frontal area: frontal line carinate between antennae from lower margin of antennal socket to 2ASD above antennal socket, line absent above; shiny impunctate triangle anterior to medial ocellus; punctation dense and crowded above antennae, separated by 1&ndash;2pd, very small and fine around inner margin of compound eye. (6) Vertexal area: shiny, with weak transverse depression; IOD = 1.7MOD, OOD = 1.85MOD, OVD = 1.0MOD; larger punctures separated by 2pd, smaller punctures closely spaced, &lt;1pd, becoming obscure posteriorly. (7) Genal and hypostomal areas: genal area as wide as compound eye in lateral view, shiny with fine punctures separated by 1&ndash;2pd, hypostomal area nearly impunctate, slightly dull posteriorly. (8) Antenna: dark brown, flagellum weakly reddish ventrally, scape, pedicel, and F1&ndash;F3 darker than F4&ndash;F10; scape reaching posterior tangent of median ocellus, subequal in length to F1&ndash;F5 (half flagellar length); pedicel slightly longer than wide, F2 and F3 subequal in size, both wider than long and shorter than F1; flagellomeres slightly increasing in length from F4&ndash;F10, F10 longer than wide. &lt;i&gt;Mesosoma:&lt;/i&gt; (9) Pronotum: shiny and impunctate, slightly dull ventrolaterally; posterodorsal margin of pronotum with complete band of hairs, including pronotal lobe which is densely outlined. (10) Mesoscutum: slightly dull; punctures of 2 sizes: larger punctures deep, separated by 2&ndash;4pd, smaller punctures shallow and more dense, separated by 1&ndash;2pd. (11) Mesocutellum: slightly impressed medially; large punctures similar to those of mesoscutum, small punctures much finer than those on mesoscutum, separated by 1pd except separated by 2pd around median line. (12) Metanotum: punctures similar to those of mesoscutellum, surface very dull; short whitish yellow hairs forming a posterior band. (13) Mesopleuron: shiny and closely punctate, punctures shallow and somewhat obscure especially ventrally, separated by &lt;2pd; pre-episternum densely and coarsely punctate, weakly granular anteriorly; hypoepimeral area and disc of episternum nearly impunctate and smooth. (14) Metapleuron: transversely striate basally, somewhat shiny and entirely impunctate. (15) Metapostnotum and propodeum: metapostnotum half as long as anterior width; posterior margin truncate, dorsally bare, basally shiny becoming weakly granular medially; propodeum posteriorly somewhat shiny, smooth and impunctate; dorsal striation absent. (16) Wings: clear, veins and stigma brown, stigma slightly more than 1/2 as long as marginal cell, membrane slightly infuscate; first recurrent vein entering second submarginal cell at 1/3 width of cell from apex. (17) Tegula: punctate anteriorly, with few long branched hairs distally, transparent posteriorly, with hyaline, dull anterior margin. (18) Foreleg: hairs pale golden on tarsi, metafemoral brush and anterior surface of tibia; coxa, trochanter, and femur with branching erect hairs; pubescence on tibia and basitarsus dense, hairs long, not branched. (19) Middle leg: as foreleg except, hairs brownish on outer surfaces of tibia and basitarsus and basitibial plate; tibia with dorsal patch of pale, long, dense pubescence on apical 2/3. (20) Hind leg: as middle leg except, coxa and trochanter with long, branching, pale pubescence; femoral scopa well formed basally with branching, long white 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, with less than 10 longer teeth; outer hind tibial spur sharply angled at apical 1/5, almost at right angle. &lt;i&gt;Metasoma:&lt;/i&gt; (21) Terga: shiny, dark brown to black basally becoming lighter brown toward slightly depressed apical area with margin somewhat hyaline; finely and shallowly punctate basally, punctures separated by 2&ndash;3pd, nearly impunctate apically; T1 entirely shiny and polished, sometimes with transverse medial dull area; T2&ndash;T5 apically shiny and polished, basally slightly dull and rough in appearance due to fine dense punctures; pubescence pale on T1&ndash;T4; darker on T5, reddish to dark brown on apical impressed area and pseudopygidial area; T1 with branching pubescence laterally and anteriorly, T2&ndash;T4 with pale whitish pubescence laterally, nearly bare medially, T5 with dense pubescence, branched hairs longer than unbranched hairs. (22) Sterna: pubescence long basally on S1; S2&ndash; S6 with hairs long, plumose and pale, brownish basally on S5&ndash;S6.&lt;/p&gt; &lt;p&gt; &lt;i&gt;Male (Allotype):&lt;/i&gt; Body length &lt;b&gt;8.0mm&lt;/b&gt;, wing length &lt;b&gt;5.4mm&lt;/b&gt;, head width &lt;b&gt;1.56&ndash;1.60mm&lt;/b&gt;, ITW &lt;b&gt;1.05mm&lt;/b&gt;. As for female except as follows: Head and mesosoma dark green. Apical margin of clypeus dark brown. &lt;i&gt;Head:&lt;/i&gt; longer than wide, L:W = 1.14&ndash;1.16. (1) Labrum and mandible: labrum basally flattened, sometimes slightly indented, distal process extending beyond basal area for up to 0.5X length of labrum. (2) Clypeus: subapical row of dark bristles absent; mandible with distinct subapical tooth. (4): Lower paraocular area: shiny, slightly dull near lower margin of antennal socket; punctures separated by 1&ndash;2pd, small and fine towards paraocular lobe; paraocular lobe very sparsely and finely punctate. (6) Vertexal area: IOD = 1.8MOD, OOD = 1.8MOD, OVD = 1.2MOD. (7) Genal and hypostomal areas: genal area slightly narrower than compound eye in lateral view. (8) Antenna: reaching anterior margin of mesoscutellum; scape reaching anterior tangent of median ocellus; pedicel about as long as wide; F1 slightly longer than pedicel, about as long as wide, longer than F2, subequal in length to F3&ndash;F10. &lt;i&gt;Mesosoma:&lt;/i&gt; (10) Mesoscutum: shiny; punctures of 2 sizes, larger punctures deep, separated by&gt;4pd, smaller punctures shallow and denser, separated by&gt;2pd. (11) Mesocutellum: slightly impressed medially; punctures similar to those of mesoscutum. (12) Metanotum: punctures slightly denser than those of mesoscutellum; surface shiny. (15) Metapostnotum and propodeum: metapostnotum sometimes with weak basolateral striation. &lt;i&gt;Metasoma&lt;/i&gt; (21) Terga: metallic reflections absent; pygidial plate broadly rounded with elevated rim, depressed medially, shiny and smooth, or with irregularly rough areas. (22) Sterna: S4 with long plumose hairs medially directed on concave apico-median area; S5 broadly concave medially, apical plumose hairs longest medially, projecting ventrally as apical tuft; S6 entire, bare basomedially, with plumose hairs medially directed. (23) Terminalia: see Figs. 98, 99.&lt;/p&gt; &lt;p&gt; &lt;b&gt;Material examined.&lt;/b&gt; MEXICO, Mexico, 16 mi. E Toluca, 9500&rsquo;, 31 July 1962, University of Kansas Mexico Expedition (holotype female [KUM]); Mexico, 20 mi. E Toluca, 8900&rsquo;, 31 July 1954, University of Kansas Mexico Expedition (allotype male [KUM]); Mexico, 15.5 mi. E Toluca, 9500&rsquo;, 6 July 1961, University of Kansas Mexico Expedition (paratype female [KUM]).&lt;/p&gt; &lt;p&gt; &lt;b&gt;Etymology.&lt;/b&gt; This species is named for the absence of striation on the dorsal surface of the metapostnotum; all other &lt;i&gt;Mexalictus&lt;/i&gt; species possess some degree of striation on the metapostnotum.&lt;/p&gt;Published as part of &lt;i&gt;DUMESH, SHEILA, 2013, &lt;/i&gt;&lt;p&gt;&lt;i&gt; &lt;strong&gt; Revision of the rare Mesoamerican bee genus &lt;em&gt; Mexalictus (Hymenoptera: Halictidae) with the description of &lt;br&gt; &lt;strong&gt; 21 new species , pp. 1-80 in Zootaxa 3708 (1)&lt;/strong&gt;&lt;/em&gt;&lt;/strong&gt;&lt;/i&gt;&lt;strong&gt;&lt;em&gt;&lt;strong&gt; on pages 22-24, DOI: 10.11646/zootaxa.3708.1.1, &lt;a href="http://zenodo.org/record/10099252"&gt;http://zenodo.org/record/10099252&lt;/a&gt;&lt;/strong&gt;&lt;/em&gt;&lt;/strong&gt;&lt;/p&gt