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Phalacrid - Stilbus - female

Phalacrid - Stilbus - Female
Bolton, Worcester County, Massachusetts, USA
May 7, 2014

Moved from Stilbus-group.

Stilbus-group, female
Moved from Shining Flower Beetles. ID'd from specimen, now a photo-voucher. Thanks Tom.

True, Stilbus or Acylomus...
...but how do you know it's a female? Was it dissected, or perhaps the ovipositor is protruding in the voucher? Only a few Acylomus have external dimorphism (in the hind tibia) while eastern NA Stilbus are (frustratingly) difficult to sex without dissection.

If the specimen is still available, have a look whether the prosternal process has a row of several long, stiff setae or whether it has just a few small setae, primarily at the outer corners. Former is Stilbus, latter is Acylomus (WARNING: character only applies to NE US species!).

It was dissected & examined
I tend to dissect these things, in the hope that future ID will be faster (at least for males) if this step is conducted when the specimen is mounted.

The prosternal process does have the row of stiff setae, so Stilbus it is. Thanks Matt!

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