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Square-headed Wasp - Crossocerus nitidiventris - female

Square-headed Wasp - Crossocerus nitidiventris - Female
Groton, Middlesex County, Massachusetts, USA
August 2, 2008
Came to the porch light.

Moved from Crabro.

Crossocerus nitidiventris, female (MA)
After checking the collection I have to revise my ID. This is C. nitidiventris. It is an unusual species in its genus because of the yellow markings on the abdomen (only present in one other species). What makes this this wasp distinctive is: yellow spots on smooth area of propodeum, yellow prepectus (that's the area just behind the pronotal lobe), rounded pronotal angles (excludes many other crabronines with similar markings), and yellow spots of similar size on terga 2-5. Excellent find, Tom! This is quite a rare species!

That's great!
When I see these different wasps, I'm not familiar enough with them to know if it's a common species I've seen many times, or something rare like this.
Matthias thanks for going to your collecyion to identify this one. I don't think anyone else that visits bugguide would have been able to get the species on this one.

To my knowledge there are no Ectemnius with yellow spots on the propodeum in the NE (this also rules out Lestica). Should be a Crabro then, perhaps in the hilaris species group.