Males in some species have distinctive midline processes on the second sternite (S2) (star) and often also on the sixth (S6) (solid arrow). In Bembix furcata, these processes are quite diagnostic. Although this would seem to makes species ID trivial for male B. furcata, there are two complications. First, these processes can be greatly reduced in some individuals, and S2 not apparently bifid, particularly in small males. Second, to see these processes (or the sternites at all), requires a nearly lateral or (ideally) ventral view. Most photos are taken from above.

The lateral view of the clypeus in this male matches the description for Bembix furcata: strongly protruberant, evenly arched in profile (dotted arrow).

Bembix furcata

In Bembix furcata males, S2 is strongly projecting (star) and often apically cleft to form two points (‘bifid’); S6 has a broad and complex projection (arrows), including a pair of angles at the outer sides and a short, blunt apicomedial point.

Male and female Bembix are best distinguished on the basis of the number of metasomal segments visible dorsally. That is, a count of the tergites. Males have 7, females just 6. Antennae also differ in the number of flagellar segments (males with 11, females with 10). However, apical segments are often short and may be difficult to count accurately in many field photos.

Bembix furcata