October 12, 2003

Mystery Bug

I saw this insect the other day in front of my office in Dartmouth. The head and thorax looked a lot like an ant, but the abdomen is pretty crazy. That end looks more like a beetle. There are two tiny shapes on top of the abdomen that look like wings or wing covers. And the thing was a shiny blue-black.

Looking it up in Patti's Peterson Guide, the closest I could come up with was that it was a "blister beetle" but the description wasn't quite right and the drawing was a little off. However, a search on the 'net shows pictures of blister beetles that exactly match my little guy.

Apparently, they contain a substance called "cantharidin" which can cause skin irritaiton and blistering. When ingested, it is a poison similar in toxicity to cyanide or strychnine.

Cantharidin is a vesicant which has been used to remove warts. You might know cantharidin under a different name. The dubious aphrodisiac, "Spanish Fly."

Posted by James at October 12, 2003 11:29 AM
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Weird... never saw one like that in my Audubon Society field guide, although they did have a listing for blister beetles. There are a lot of different varieties and I guess some of them are VERY different.

With some bugs (though not especially beetles) you need more than one picture because bugs look very different from one stage to the next. Most books I've found don't cover all the stages. :(

Posted by: julie at October 12, 2003 11:00 PM

I certainly had never seen an insect like that before. I'm kicking myself now for not putting a ruler next to it, but the thing was somewhere between an inch and two inches.

Posted by: James at October 13, 2003 11:47 PM

That big?? Wow.

There was a bug we used to see a lot at the house in Taunton, especially around the lilac bushes. It was closer to 1/2 inch and was kind of purplish. It had a broad, flattish abdomen. I'd know it if I saw it again, but I never saw a bug like it anyplace else, and it's not in any of my bug books.

Posted by: julie at October 14, 2003 10:10 AM

I'm going to look and see if I can find another one later this afternoon. It was probably closer to an inch, or maybe 1.5.

Yeah - looking at my finger, it looks like a two-knuckler on my index finger, which i think comes out to about 1.5 inches.

I have to start carrying a ruler around.

Posted by: James at October 14, 2003 10:47 AM

I'm glad you finally identified your insect friend. I'm glad you didn't touch it (or, god forbid, eat it).

Posted by: Patti M. at October 15, 2003 12:50 PM

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