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Photo#141761
Mysterious Black Bug That Attacks - Ocypus olens

Mysterious Black Bug That Attacks - Ocypus olens
Clackamas, Clackamas County, Oregon, USA
August 31, 2007
Size: 1 Inch
I have found 4 bugs all around the yard. I have found two walking in the drive way, one under a rock and another approx. 3 feet underground while I was digging a trench. They are aggressive bugs that try to bite, and raise their butt end. If they are grabbed they excrete a white liquid from their butt end. The inside of their mouth is red, and they appear to have two sets of pinchers. They look really similar to Termites, but seem too big to be a termite. Please help with identification.

O.olens distribution.
The species has been recorded first in California in the 1970ies, I believe, and it may be that it only recently spread into Oregon.

 
One of the bugs bit my neck.S
One of the bugs bit my neck.Should i be worried?

 
No.
It is not venomous and if it didn't draw blood then there is no pathway for normal infection.

 
OK because it didnt draw bloo
OK because it didnt draw blood.

 
ok because it didnt draw bloo
ok because it didnt draw blood

 
no it didnt draw blood so i s
no it didnt draw blood so i should be alright

The "butt fluid"
is defensive chemicals. Although there is one rove beetle genus that emits chemicals strong enough to blister the skin, it is not this genus. Just wash your hands before putting them in your mouth :-)

 
Rove Beetle?
You mentioned the butt fluid, and a possible pinch from the pincher....any other problems that these bugs may cause? Damage to houses? Where do they come from? I've never seen one, and then out of nowhere I have 4 within a 2 day period. Thank you for any information that you may have.

Nick

 
Hi Nick,
Rove beetles are a good thing to have around.

Very likely a female laid her eggs on your property, the larvae hatched and prospered, eating small insects and other invertebrates, pupated, and emerged at about the same time, accounting for your little population explosion. Both adults and larvae are predacious on other insects. Some rove species eat fungus and fungus gnat maggots but none eat wood or vegetable gardens (athough a few tiny odd-looking ones consume pollen).

Species identified
Size, and totally opaque dorsal surface exclude similar species.

Ocypus?
I agree. Possibly, it belongs to the genus Ocypus or Tasgius, previously considered as subgenera of Staphylinus.

Confront at: http://bugguide.net/index.php?q=search&keys=ocypus&search=Search

Rove beetle
A beetle, family Staphylinidae. Harmless, except for a slight pinch from the mandibles.

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