Identification, Images, & Information
For Insects, Spiders & Their Kin
For the United States & Canada
Argid Sawfly - Arge humeralis

Argid Sawfly - Arge humeralis
DuPage County, Illinois, USA
July 21, 2004
This sawfly is a great mimic of this Braconid wasp:

At least I think the sawfly mimics the wasp; that's not for sure.

mimicry in braconids and sawflies
I ran across your comment looking at images of sawflies. I suspect the mimic is actually the Braconid--there are several with that pattern. I don't think the Braconids have a harsh sting, but I see some research out there that many sawflies have chemical defenses as larvae, for instance:
Endogenous toxins and the coupling of gregariousness to conspicuousness in Argidae and Pergidae sawflies
It would certainly make sense that some adults retain the chemical defenses of the larvae.
I'll post a note here if I find any more information.

Argid Sawfly, I think
Family Argidae, I believe, antennae have three segments, last one very long. Arge as a widespread eastern genus, but there are others.

(Your other sawfly recently posted is not from the same family--antennae have many segments.)

Patrick Coin
Durham, North Carolina

Arge humeralis
I believe you are correct, Patrick. I found some images that are certainly the same insect, listed as Arge humeralis.
I have not found any other corroborating data as yet. Check it out: Argid sawflies

Arge humeralis
I think you've got it right. Check out my picture that David R. Smith (Eric Eaton asked him to do sawfly ID's on my website last year)identified for me.