Reprinted with permission of the American Entomological Society from:
LaBerge, W. E. 1971b. A revision of the bees of the genus Andrena of the Western Hemisphere. Part IV. Scrapteropsis, Xiphandrena, and Rhaphandrena. Transactions of the American Entomological Society 97: 441-520.
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This small species is related to A. morrisonella and A. fenningeri. The female of alamonis differs from that of any of the Scrapteropsis described above by its broad head and short vertex. This female lacks the hind femoral ventral ridges of the alleghaniensis-group and has the short sternal apical areas of the imitatrix-group. The male is similar to the female in having short sternal apical areas, a broad head and a short vertex. In addition, the male has a reflexed sixth sternum and relatively long first flagellar segment as in alleghaniensis. The male is here described for the first time.
FEMALE. MEASUREMENTS AND RATIOS. — N = 20; length, 8-10 mm; width. 3.0-3.5 mm; wing length, M = 3.71 ± 0.126 mm; FL/FW, M = 0.99 ± 0.006; FOVL/FOVW, M = 3.37 ± 0.044.
INTEGUMENTAL COLOR. — Black except as follows: mandible with apical half rufescent at least in part; flagellar segments 2- or 3-10 dark brown to dark reddish-brown below; wing membranes hyaline, colorless or slightly infumate. veins dark brown to dark reddish-brown; distitarsi dark rufescent; tibial spurs testaceous.
STRUCTURE. — Antennae as in imitatrix but segment 2 about as long as 3 and these two segments quadrate. Eyes each about three and one-third to three and one-half times as long as broad, inner margins converging slightly toward mandibles. Malar space, mandible and galea as in imitatrix except galea dulled by fine tessellation. Maxillary palpus as in imitatrix but segmental ratio about 0.8: 1.0: 0.6: 0.6: 0.4: 0.5. Labial palpus as in imitatrix but ratio about 1.0: 0.5: 0.4: 0.5. Labral process as in alleghaniensis but narrow apical part often less than half length of process; labrum apically as in alleghaniensis. Clypeus as in imitatrix but punctures somewhat smaller and impunctate median line broader. Supraclypeal area with extremely small, well-separated punctures and fine reticular shagreening dulling surface. Genal area as in imitatrix but slightly broader than eye in profile. Vertex above lateral ocellus equal to about half an ocellar diameter, dulled by minute obscure punctures and fine regular tessellation. Face above antennal fossae as in imitatrix. Facial fovea as in imitatrix, separated from lateral ocellus by less than one ocellar diameter.
Pronotum as in imitatrix. Mesoscutum with small round punctures posteromedially separated mostly by two to five puncture widths, peripherally by half to one puncture width or less. surface dulled by regular reticular shagreening. Scutellum with slightly larger punctures crowded posteriorly and medially, sparser anterolaterally, surface shiny. Metascutum with small crowded punctures and shagreening. Propodeum with dorsal enclosure irregularly and rather finely rugose; dorsolateral and posterior surfaces granular, extremely finely punctatorugose and tessellate; lateral surface dull. with scattered punctures and coarse tessellation. Mesepisternum with small scattered punctures posteriorly becoming crowded anteriorly and contiguous in upper third, surface dulled by coarse tessellation. Wing venation as in imitatrix but pterostigma somewhat narrower. Legs as in imitatrix but hind tibia narrow, broadest at apex: hind femur without ventral ridges.
Metasomal tergum 1 with basal area punctures separated mostly by two to three puncture widths, apical area punctures by half to one puncture width (punctures smaller than basally), surface shiny. Tergum 2 with both apical and basal area punctures separated mostly by one to two puncture widths or less, surfaces shiny. Terga 3 and 4 similar to 2 but punctures progressively slightly sparser. Pygidial plate and sterna as in imitatrix with sternal apical areas extremely narrow (sternum 2 with apical area equal to less than one-fourth median sternal length).
VESTITURE. — Generally white to pale ochraceous being ochraceous on vertex and thoracic dorsum. Distributed as in imitatrix except propodeal corbicula without plumose hairs anteriorly and internal hairs entirely simple.
MALE. MEASUREMENTS AND RATIOS. — N = 5; length, about 9 mm; width, about 2.5 mm; wing length, M = 3.42 ± 0.147 mm; FL/FW, M = 1.01 ± 0.008; FS1/FS2, M = 1.03 ± 0.059.
INTEGUMENTAL COLOR. — Black with same exceptions as in female but tergal apices at least narrowly rufescent.
STRUCTURE. — Antennae as in imitatrix but flagellar segment 1 longer, as long as second segment or slightly shorter or longer. Eyes as in imitatrix. Malar space, mandible and galea as in female. Maxillary palpus as in imitatrix but segmental ratio about 0.8: 1.0: 0.7: 0.6: 0.5: 0.5. Labial palpus as in imitatrix but ratio about 1.0: 0.4: 0.3: 0.4. Labrum as in female but process broader and more deeply emarginate. Clypeus a\ in female but impunctate median line represented by a narrow zone of sparser punctures. Supraclypeal area as in female. Genal area at least one and one-half times as broad as eye in profile, without fine longitudinal rugulae laterally, with small sparse punctures and fine tessellation dulling surface. Vertex as in female. Face above antennal fossae as in female but rugulae more irregular, less longitudinally orientated.
Thoracic sculpturing and form as in female except as follows: mesoscutal posteromedian area of sparse punctures smaller; mesepisternum with punctures slightly less crowded anteriorly; propodeum with lateral surface more densely punctate and duller. Wing venation as in female. Legs as in imitatrix but hind tibia not swollen, broadest at apex.
Metasomal terga 1-5 sculptured as in female terga 1-4 but punctures usually slightly sparser. Sterna 2-5 as in female sterna 2-4 but basal area punctures separated mostly by one to two puncture widths (by more on tergum 2). Sternum 6 reflexed apically as in fenningeri.
Terminalia as in figures 22-26; note the following: sternum 7 with emargination relatively shallow, lateral lobe truncate; sternum 8 with basal part relatively small: gonocoxite with dorsal lobe as in imitatrix: penis valve narrow. tip small.
VESTITURE. — Generally white; form and distribution as in imitatrix.