Species Rasahus biguttatus

Rasahus biguttatus (Say, 1832)

16-20 mm (1)

The coloration that separates Rasahus biguttatus and Rasahus hamatus is much more clear in Fracker (1912). Part of the key reads as follows:

c. Costal margin of hemelytra pale at base

d. No transverse vitta at base of membrane....2. biguttatus Say

dd. Transverse pale vitta at base of membrane....3. sulcicollis Serv. [Mexico]

cc. Costal margin of hemelytra black to base; elytra with a narrow ochreous patch on corium and clavus....4. hamatus Fabr.

Blatchley (1) gives the following description (link):

Very similar to hamatus; the chief differences as in key. Color variable, the head and pronotum often reddish-brown, sometimes with front half of latter black and hind one brown. Membrane blackish with a large oval or rounded yellowish spot at middle. Connexivum in both sexes with wide alternate blackish and yellow spots; legs usually reddish- yellow, paler at base, often in great part blackish.... Both (biguttatus and hamatus) vary widely in the yellow markings of elytra and legs. The only structural difference between the two seems to be the narrower form of the males of hamatus.

Rasahus hamatus (and presumably other species), said to be able to deliver a painful bite (Missouri Conservationist).