LaBerge (1986) states that males are easily recognized to this subgenus by the yellow clypeus, distinct pronotal humeral angles, and the large, well-formed pygidial plate of metasomal tergum 7.
Females are less distinctive. They do have very large pygidial plates, an apical fasciae on tergum 1, and an unusually short first flagellar segment.
For more information, see LaBerge, Wallace E. 1986. A revision of the bees of the genus Andrena of the Western Hemisphere. Part XI. Minor subgenera and subgeneric key. Transactions of the American Entomological Society 111: 441-567.
Tibial scopa highly plumose, mostly in Florida peninsula...A. dimorpha
Tibial scopa usually less plumose, mostly in Florida panhandle...A. banksi
Conspicuous yellow maculae between clypeus and eyes, mostly in Florida peninsula...A. dimorpha
Lateral face marks either lacking or with mere traces of yellow along clypeal margin which do not extend to margin of eye, mostly in Florida panhandle..A. banksi
County Records: Alachua, Leon, Liberty, Okaloosa. With the exception of Alachua, most of the records of this species are from the panhandle of Florida.
Locations:
Dates: March 15-April 15, March: 1, April:4; further north it flies from March 11-May 19.
Plant: Crataegus, Prunus angustifolia; elsewhere (LaBerge 1986) it has been collected on Diospyros virginiana, Prunus caroliniana, Prunus sp., Pyracantha sp., and Salix spp.
Notes: This is a new State record for Florida. Previously collected in Mississippi, Georgia and Alabama. This is a primitive species in the subgenus. Females have a bowed out, almost impunctate clypeus, large blunt or apically rounded pygidial plate, short malar space, and well formed tergal fasciae. Males are distinctive in the large well formed pygidial plate, yellow clypeus, and the genal area with posterior process from near the midpoint of the hind margin.
County Records: Alachua, Highlands, Hillsborough, Lake, Okaloosa, Orange, Pasco, Putnam, Sarasota. With the one exception of the collection from Okaloosa, most of the records are in Peninsular Florida.
Locations: Archbold Biological Station, Destin, Gainesville, Interlachen, Orlando, Sarasota, Tampa
Dates: March 13-April 15; March:5, April:1; LaBerge reports flight times across the entire range north to New Jersey are March 23-April 24.
Plant: Conradina canescens from Florida. No floral records are listed in literature.
Notes: This is a smaller species than A. banksi and is rare in collections. It resembles A. banksi in the weakly punctate clypeus, short first flagellar segment, and large pygidial plates in both sexes. Females are distinctive in the malelike, elongate antennae, plumose tibial scopal hairs, plumose corbicular hairs and males have well-formed basal mandibular teeth, parocular yellow spot, and apical fasciae on terga 2-5. Males also have the genal process similar to males of A. banksi.
