Male, hind leg, underside of basitarsus, in the region between where the two tibial spurs bracket the basal portion of the basitarsus

No ridge present, integument uninterrupted and smooth
This ridge can be difficult to see in some species. It is often hidden by light hairs, and may appear as a shark s fin rising through the hairs. It may be yellow or brown. The ridge can be found on the basitarsus in the same plane as where the two tibial spurs occur on the tibia.

© Kimberly Huntzinger, 2007
Agapostemon coloradinus, male, hindbasitarsus, parallel mtg