Oil Beetle

Large black beetle?
Location: East-Central New Jersey
November 17, 2010 9:47 am
Found this while gardening. It’s about an inch and 1/2 long. My hand is included for scale. Looks like a cross between a large ant and a wasp. Couldn’t find it in my Mid-Atlantic field guide — what is it?
Signature: Jennifer

Oil Beetle

Hi Jennifer,
The large, black, flightless Blister Beetles in the genus
Meloe are known as Oil Beetles because they are able to secrete a substance known as hemolymph.  The hemolymph is somewhat oily and it contains a compound known as cantharidin which can cause blistering of skin.  You should avoid handling Oil Beetle as well as other Blister Beetles in the family Meloidae.

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