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Beetle - Eleodes marginata

Beetle - Eleodes marginata
Point Reyes National Seashore, Marin County, California, USA
May 22, 2007
Size: 1.5 cm
On the ground in bishop pine/Douglas fir forest.


Eleodes (Discogenia) marginatus

Def not Coelocnemis...
Moved tentatively to Eleodes, don't really see what else it could be, except maybe Neobaphion, but I doubt that.

Moved from Coelocnemis.

maybe not Coelocnemis
if it was really 1.5 cm, thats way too small for a Coelocnemis. Also I don't think they occur on the seashore. If you kept the bug, check its tarsi. If there are no golden setae (doesn't look it in the photo) then it isn't Coelocnemis. There are some eleodes that are this small and look like this. Even if not in the genus, Eleodes, pretty sure its at least in the tribe Eleodini.

darkling beetle
we have an expert, he may tell more.

No expert here, but....
I am relatively certain this is a species of Coelocnemis (very wide thorax is typical of the large members of this genus).

darkling beetle
That genus isn't in the Peterson Field Guide series book on beetles. Could it be a name change? Maybe just the limitations of the book in a family with 180 genera. Do you have a beetle book you recommend?

"Field Guide to the Beetles of California"
by Arthur Evans. (Also get a copy of his "An inordinate fondness for beetles", a really tasty coffee table book. I got it from my county library.)

Darkling is very common, at least locally. There are a couple of pages on them in "Kaufman Field Guide to Insects of North America", written by Eric R. Eaton.

Seconded. I think yours is what is called a stink beetle here.
They stick their butt up in the air and spray to ward off attack. Here's one that looks like yours:

BTW, I'm no expert either, as you've probably gathered from my highly scientific explanation of behavior.

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