Within the Scutellinitens group, A. robervalensis may be distinguished from A. scutellinitens by the clypeus less protuberant, and from A. specularia by the scutellum tessellate and dull. A. robervalensis has much more black hair than the other two species and the wings are more clouded apically. In size, disposition, and coloration of vestiture, A. robervalensis is much like A. peckhami, but is widely separated from that species by the inner margin of the compound eye diverging slightly above except for upper end incurved, and the males without a strong genal ridge.
Female. Measurements and ratios. — N = 20; length, 8.5-11.2 mm; width, 2.6-3.6 mm; wing length, M=3.00± 0.192 mm; FL/FW, M = 1.01 ± 0.131; FOVL/FOVW, M = 3.17 ±0.158.
Integumental Color. — Black except as follows: antennae with flagellar segments ventrally becoming brown apically; mandible with apical half red; tibial spurs nearly white; tarsal claws with basal half yellow, apical half red; tegula and pterostigma medium brown; wing veins yellow brown; wing membrane hyaline except for apical area moderately darkened; metasomal terga and sterna with moderately wide hyaline apical area; pygidial plate red.
Structure. — Scape longer than flagellar segments 1 to 3; pedicel and flagellar segment 1 equal to flagellar segments 2 to 4; flagellar segment 1 longer than flagellar segments 2 plus 3. Eye 4 times longer than wide with inner margin diverging slightly above except for upper end incurving. Malar space almost 10 times wider than long. Mandible in repose projecting for one-fourth its length beyond middle of labrum with notch of mandible tooth equidistant between middle of labrum and mandible apex. Galea moderately tessellate, dorsal surface wider than lateral surface. Maxillary palpus with half apical segment projecting beyond apex of galea; segmental ratio 0.7:1.0:0.8:0.8:0.7 :0.9. Labial palpi with basal segment flattened laterally, curved, apical segment attached subapically, segmental ratio 1.2:0.8:0.6:0.8. Labral process flat except emarginate area slightly reflexed, twice as wide as long, median emargination depth one-fourth length of labral process. Clypeus moderately protuberant, extending below level of eyes for one-third its length, with large punctures medially separated by 2 diameters, puncture size decreasing dorsolaterally, shagreened throughout but shagreening weak medioventrally. Supraclypeal area densely shagreened with large punctures between antennal fossae. Genal area one-third wider than eye, with reticular shagreening and small punctures separated by 4 diameters throughout, except shagreening weak near eye. Vertex above lateral ocellus slightly wider than 1 ocellar diameter, moderately tessellate, with medium-sized, deep punctures separated by 1 diameter. Supra-antennal area longitudinally rugulate. Facial fovea of equal width throughout, rounded above and below, reaching above to a line through middle of lateral ocellus, below to a line nearly half way between lower margin of antennal fossa and upper margin of clypeus.
Pronotum with humeral angle and ridge well developed, not depressed where crossed by weak pronotal suture, shagreened throughout. Remainder of mesosoma dorsally moderately tessellate. Scutum with medium-sized, scattered punctures, punctures tessellate internally. Scutellum with tessellation weak anteriorly, nearly shiny. Metanotum with large punctures, closely grouped in lateral thirds. Propodeal enclosure with broad anterior band of irregular, longitudinal rugulae and shallow, longitudinal, median depression. Dorsoposterior surfaces with medium-sized punctures separated by 2 diameters. Propodeal corbicular area with reticular shagreening and scattered punctures in anterior fourth. Mesepisternum moderately tessellate with medium-sized punctures throughout separated by 2 to 3 diameters. Metepisternum with weak, reticular shagreening, lower half nearly shiny. Mesobasitarsus widest medially, 3 times longer than wide, equal in width to metabasitarsus. Metabasitarsus widest basally, 3.5 times longer than wide, five-sixths as wide as metatibia. Metatibia widest apically, 3.3 times longer than wide. Pterostigma 4 times longer than wide, vein 1st m-cu meets second submarginal cell one-fourth of distance from apex.
Metasomal terga 1 to 5 weakly tessellate, tessellation weaker on apical depressed areas, terga 1 to 4 with small punctures on discs separated by 6 diameters except more closely spaced on posterior margin of disc. Tergum 5 with larger punctures separated by 2 to 3 diameters. Pygidial plate narrowly rounded apically, recurved, lateral edges and median area only slightly raised, basal half with small, close punctures, apical half impunctate. Sterna 1 to 6 with weak, reticular shagreening; sternum 1 with small, median, V-shaped, apical emargination, and medium-sized punctures separated by 3 diameters; sterna 2 to 6 with broad, median, basal impunctate area, remainder with small punctures separated by 2 to 3 diameters.
Vestiture. — Clypeus with sparse, brown hairs except naked along narrow, median area. Facial fovea with hairs dark brown-black. Supraclypeal area and vertex with scutum, scutellum and pronotum with intermixed white and brown hairs. Remainder of mesosomal hairs white or nearly white. Propodeal corbicular area with widely spaced hairs in anterior fourth. Legs with hairs black or nearly black except for white hairs of meta-coxa, -trochanter and -femur, and black apical femoral fringe, and tibial scopa with ventral hairs white. Trochanteral floccus imperfect. Metasomal tergum 1 with sparse, erect, long, white hairs throughout, more numerous laterally, forming a sparse, apical fascia. Terga 2 to 4 with thin, apical fasciae of short, white, nearly appressed hairs obscuring one-third of terga. Tergum 2 with posteriorly directed long hairs on median third, with short, black, erect hairs in lateral thirds. Terga 3 to 4 with short, black, erect hairs on discs. Tergum 5 with long, posteriorly directed or appressed black hairs throughout. Sternum 1 with erect, white and black hairs, sterna 2 to 5 with subapical fimbriae well developed in lateral thirds, nearly white on sternum 2, becoming more black posteriorly. Sterna 1 to 5 with sparse, apical fringes of brown-black hairs. Punctured areas of sterna 2 to 6 with black, erect hairs, short laterally.
Male. Measurements and ratios. — N = 2; length, 7.6-8.2 mm; width, 2.4-2.5 mm; wing length, 2.60-2.68 mm; FL/FW, 0.94; FS1/FS2, 1.33.
Integumental Color. — Black except as follows: antenna less colored ventrally beyond second flagellar segment; mandible with apical third red; tibial spurs nearly white; distitarsi red-brown; tarsal claws with basal half yellow, apical half red; tegula, wing veins and pterostigma dark brown; wing membrane hyaline except for broad, apical area moderately darkened.
Metasomal terga and sterna with moderately wide apical margin hyaline.
Structure. — Scape slightly longer than pedicel plus flagellar segments 1 plus 2, about equal to flagellar segments 1 plus 2 plus half of flagellar segment 3; flagellar segment 1 longer than flagellar segment 3. Eye 3.3 times longer than wide, with inner margin diverging slightly above except for extreme upper limit incurved. Malar space, mandible, and galea as in female. Maxillary palpus with half of apical segment projecting beyond apex of galea; segmental ratio 0.6:0.9:0.7:0.8:0.8:0.8. Labial palpus with basal segment flattened, curved laterally, apical segment attached subapically, segmental ratio 1.1:0.5:0.5:0.7. Labral process strongly recurved, twice as wide as long, apical emargination depth one-third length of reflexed area. Clypeus nearly flat, extending below eyes for less than one-half its length, with small, medioventral, depressed, impunctate area; remainder with large punctures separated by one-half diameter, very narrow upper peripheral area with very light shagreening, surface shiny. Supraclypeal area as in female. Genal area more than 1.5 times wider than eye, produced posteriorly opposite midpoint of eye to a blunt projection, sculptured as in female. Vertex above lateral ocellus 1.3 times diameter of ocellus, sculptured as in female. Supra-antennal area as in female. Parocular area above base of antenna sculptured as for supra-antennal area, below antenna punctured as for clypeus.
Pronotum with humeral angle and ridge well developed, almost carinate, pronotal suture very weak, humeral ridge not depressed where reached by pronotal suture, area above pronotal suture with weak, vertical rugulae, remainder of pronotum with reticular shagreening, reticular shagreening weak below pronotal suture, this area shiny. Remainder of mesosoma sculptured as in female except lateral propodeal area weakly tessellate.
Metasomal terga 1 to 5 sculptured as in female metasomal terga 1 to 4 except tessellation very weak, surface shinier. Sterna much as in female, shinier. Sternum 7 (fig. 53) with basal apodemes narrowing anteriorly; with a broad, V-shaped emargination apically, processes on each side of emargination pointed with long hairs. Sternum 8 (fig. 54) with apex and neck region almost twice as long as basal region, apex pointed; neck area with abundant, long hair. Gonoforceps (figs. 50 to 52) in dorsal and lateral view strongly ridged. Penis valves in dorsal and ventral view strongly expanded basally, narrowing gradually apically, except apex rounded, lobe-like; in lateral view strongly bent downwards below gonoforceps.
Vestiture. — White except as below: clypeus with long, abundant pubescence. Terga 1 to 5 with weakly formed, apical fasciae, width one-third width of terga. Tergum 1 with long, erect hairs on disc, tergum 2 with shorter hairs on disc, some of these hairs black-brown. Terga 2 to 5 with shorter, sparse, black hairs on discs, posteriorly directed. Sterna 2 to 6 with long hairs projecting posteriorly.
Variation. — In females the proportion of white to black or nearly black hairs may vary. In most females the two long tufts of hairs projecting from the clypeus are brown. The hairs lying laterally over the facial foveae are mostly black or nearly black. The scutum may have mostly white or mostly black hairs. The small impunctate area may be nearly absent. The holotype female has only 2 submarginal cells in each wing, and metasomal tergum 1 is without a fascia, but this lack of a fascia is probably a result of wear.
Reprinted with permission from: Mitchell, T.B. 1960 Bees of the Eastern United States. North Carolina Agricultural Experiment Station Technical Bulletin No. 141.
FEMALE—Length 10 mm.; clypeus slightly convex, rather short, projecting about one- third below suborbital line, surface rather dull, with rather fine, scattered, irregular punctures on each side of an obscure, median, impunctate line; facial foveae narrow, occupying above little more than half of space between eyes and lateral ocelli, covered with fuscous tomentum; space between margin of vertex and lateral ocelli about equal to their diameter; cheeks slightly broader than eyes, rounded posteriorly, rather smooth, punctures exceedingly minute and obscure; malar space very short; basal segment of flagellum fully equal to 2nd and 3rd combined, these rather short; process of labrum rather broadly sub- triangular, apex truncate, obscurely incised medially; mandibles of moderate length, with a distinct, inner, subapical tooth; pubescence of head rather short, entirely pale on clypeus and on cheeks below, more fuscous on inner margins of eyes and on upper part of face, cheeks and vertex; pubescence of scutum and scutellum rather short, erect, fuscous, that on pleura, propodeum and legs in general pale, thoracic integument dull and tessellate, scutum and scutellum very sparsely and minutely punctate, scutellum somewhat more shining, pleura lacking distinct punctures; enclosure of propodeum smooth, almost shining, with a very narrow fringe of obscure, minute striae; propodeal corbicula whitish, well developed but rather short, with a rather thin anterior fringe; trochanteral floccus rather thin, white; tibial scopa rather dense, hairs rather elongate and simple, pale except for some darker basal hairs; fore and hind basitarsi distinctly narrower than their respective tibiae, the mid basitarsi nearly equalling their tibiae in width; 2nd submarginal cell much shorter than 3rd, receiving 1st recurrent slightly beyond middle; abdominal terga smooth but dull, microscopically tessellate, impunctate, apical margins very slightly and narrowly depressed, terga 2-4 with conspicuous, whitish, apical fasciae, discal pubescence short, erect, blackish.
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