Physomeloe corallifer (Meloidae)
(Epicauta pennsylvanica (Coleoptera: Polyphaga: Tenebrionoidea: Meloidae: Meloinae: Epicautini). South Run power line cut, Fairfax County, VA 26 September 2012
Epicauta pennsylvanica (Coleoptera: Polyphaga: Tenebrionoidea: Meloidae: Meloinae: Epicautini). South Run power line cut, Fairfax County, VA 14 October 2012
This Blister Beetle (Meloe sp., tentatively angusticollis, or Short-winged Blister Beetle) is a member of the Family Meloidae (all blister beetles) and can exude a chemical from its leg joints that sometimes causes blisters on human skin. Meloe angusticollis is in the sub-family Meloinae and members of the genus Meloe are sometimes called "oil beetles." My specimen seemed to be slightly less than an inch long. My Audubon field guide lists the Short-winged Blister Beetle as 5/8 inch or less, but this one seemed larger. There’s more than one species, and there’s a difference in the size of the two sexes. Males often have a bend in the antennae about midway along the 11 segments and this one seems to fit that description. However, in other photos I've seen of them mating, the male is shorter, assuming "he" is the one on top. I've never seen more than one at a time, so comparisons in the field are a little difficult. I therefore assume the kink in the males' antennae is more pronounced. This blister beetle is dark steel-blue and has a finely pitted & crinkled surface. The front wings (called elytra) cover part of the abdomen, but there are no hind wings and the beetle is unable to fly. Adults can be found wandering about in spring and fall; this one was 3/23/12. They eat the leaves of vegetables and weeds. Their eggs are laid near wild bee nests and the beetle larvae become parasites of the bees. Most of this information is taken from my blog at http://northeastnaturalist.blogspot.com/2012/03/blister-beetle.html More species of Meloe can be found on BugGuide at http://bugguide.net/node/view/303/bgimage?from=0
photo refs.: Beetle,Blister_©DaveSpier_D076602iN and Beetle,Blister_©DaveSpier_D076630iN (Camera EXIF date is wrong due to internal battery failure.)
Oily Blister Beetles -- still need a species ID. Taken in a forested area on Sandy Hook, NJ (mature mid-Atlantic barrier-beach community, holly & deciduous trees). They're huge -- the top one is ~3.5 cm (1.4") long. Best large.
Blister beetles are beetles (Coleoptera) of the family Meloidae, so called for their defensive secretion of a blistering agent, cantharidin. There are approximately 7,500 known species worldwide. Many are conspicuous and some aposematically colored, announcing their toxicity to would-be predators.