oil beetle

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Any of various blister beetles of the genus Meloe that exude an oily yellow substance from the joints of the legs when disturbed.

from The Century Dictionary.

• noun Any coleopterous insect of the genus Meloë in a broad sense: so called from the oil-like matter which they exude.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun any of various beetles that exude an oily substance from the leg joints that deters enemies