Excerpts from Jim Conrad's
from the December 16, 2012 Newsletter issued from the valley of the Dry Frio River in northern Uvalde County, southwestern Texas, on the southern border of the Edwards Plateau, USA
AN ANT-MIMICKING BUG
A large, black ant prowled the hairy undersurface of a dried-up leaf on a bush, but there was something funny about that ant. It didn't move right, and somehow it looked odd. That's what I saw below.
Up close it looked more like an ant than ever, except for two things: it bore immature wings, something I've never seen on an ant, and; more un-anty still, for mouthparts it bore a strawlike proboscis, while ants are equipped with chewing mouthparts. This was no ant, but certainly it was mimicking an ant. Some ants that size can inflict a painful bite, so maybe that's the reason a non-ant bug might want to play the part of an ant.
Volunteer identifier Bea in Ontario figured out that our antlike bug is a real bug -- a member of the True Bug Order the Hemiptera -- and the Broad-headed Bug Family, the Alydidae. She even thinks it's probably the Texas Bow-legged Bug, HYALYMENUS TARSATUS, though positive identification of that little-documented species is so rare that it's hard to be sure.
The Texas Bow-legged Bug occurs here and there throughout most of tropical America, and in the US in Texas. It feeds on beans in pods of certain legume species, but it seems to occur in such small populations that it seldom causes much crop damage.