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Photo#246814
Chlaenius  - Chlaenius pennsylvanicus - male

Chlaenius - Chlaenius pennsylvanicus - Male
Medford, (~25 miles east of Philadelphia, PA) Burlington County, New Jersey, USA
June 1, 2008
Size: ~12mm
wish I had shot this one more top-down, but a nice green one. Might be C. impunctifrons Say?
came to UV light

Images of this individual: tag all
Chlaenius  - Chlaenius pennsylvanicus - male Chlaenius  - Chlaenius pennsylvanicus - male

Moved

Chlaenius pensylvanicus Say
i'm pretty confident
IMPORTANT NOTE: A typo in D&A key for Agostenus (p.164) mislead you: in the very first couplet, the ‘–’ part (“tip of prosternum not margined…”) should refer to couplet 6, not 5!!! Took me a few min to figure it out. Another horrible error fooled me much longer: in couplet 1 of the Chlaenius s.str. key (p.163), references ‘2’ and ‘4’ should be switched, i.e. ‘abdominal sclerites smooth…’ is supposed to send you to couplet 4 rather than 2...
go figure...

Moved from Vivid Metallic Ground Beetles.

 
Yes,
relative antennomere lengths and dorsal color is consistent with C. pennsylvanicus. I just didn't feel as comfortable as you without seeing perpendicular view of head, labrum, and pronotum. Couplet #1 under Chlaenius s. str. is correct. Better wording would have been:

1. Abdominal sclerites glabrous medially or at least distinctly less pubescent compared to lateral portions...

- Abdominal sclerites uniformly punctate/setose...

Angularity of humeral angle is perhaps a more observable and reliable character which is also addressed in couplet #1.

Finally, double "nn" in "pennsylvanicus" is the correct spelling for this species. BugGuide page should be corrected.

 
thanks, Peter
n inserted

Chlaenius
is safest level in my opinion as the unfortunate oblique view of dorsum prevents me from seeing the true shape of the taxonomically-important pronotum. An exact perpendicular dorsal view is most helpful.