Moved from Pyrgotidae.

...from the clear "strong constriction near the basal 3rd of the hind tibia" cited as the key character in Steyskal's 1978 synopsis of NA Pyrgotidae (see couplets 9 and 10 on 3rd page therein).

Also, Gary Streck cites the distinctive banding of the tibiae as characteristic of "Pyrgota" maculipennis in his comments beneath the post below:



The tibial bands character seems good to me, and I guessing Gary noted it from viewing various vouchered specimens, since I haven't seen that character mentioned in any references I've been able to find. But I'm sure there are more ref's than I've found...and besides that, many good characters often go unmentioned in references anyway. Not that I mean to imply that any character one happens to notice is necessarily consistent throughout a large series of specimens of a species.

But having said that it seems to me that the pattern of dark spots on the vertex (and occiput) is distinctive between "Pyrgota" maculipennis and Sphecomyiella valida .

By the way, the reason I keep putting "quotes" around the genus name Pyrgota here is because it seems likely that the currently valid name here is Boreothrinax maculipennis. See comments accompanying the post below for details:

Moved from Acalyptratae.