Expert: Eric R. Eaton - 6/28/2006

Question
I live in the central California low foothills, very dry during the summer. Every year I am plagued by paper wasps, and am well familiar with them. However, I saw one the other day (June 26, 2006) which I've never seen before. This one is much larger than a paper wasp (nearly twice the size), and has a mostly black body. I don't totally remember, but it seemed like it might have a light hairy covering. It had dark, smoky-colored wings, but what set it apart mostly were the eyes. They were kind of a very pale yellow, almost an off-white, and they really stood out set against the black body. I sprayed one and, as it was dying, I kept seeing the stinger going in and out, so it definitely has one. Unfortunately, I threw it away before I thought to ask you, so my description is from memory. Now, this morning (2 days later), I just saw another one flying around (about 9:30 a.m., on a very warm morning). I'm familiar with mud daubers, yellowjackets, bees, and paper wasps, but have never seen one like this. Can you help identify it? Thanks in advance.

Answer
Larry:

You are probably describing some kind of scoliid wasp, family Scoliidae.  They have no common English name.  Females and males often look very different from each other.  Females dig up scarab beetle grubs, sting them to paralyze them momentarily, lay an egg, and then leave.  The larva that hatches from the egg then feeds as an external parasite on the beetle grub until it devours it completely.

Try looking up the family name on the 'net, especially the genus Campsomeris.  That is probably your critter.

Eric
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