darkling beetle

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

• noun Any of numerous beetles of the family Tenebrionidae, having a brown or black body, feeding on decaying vegetation, living plants, or stored grain, and inhabiting a variety of habitats, including deserts.

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

• noun sluggish hard-bodied black terrestrial weevil whose larvae feed on e.g. decaying plant material or grain