E. convexum, female

Moved from Eusphalerum.

for getting that great explanation from Dr. Thayer.

Yes, that's a very nice shot of a female Eusphalerum, though unfortunately the North American species have not been revised, so I can't give you a species name. Based on the relatively scanty published records, there are at least four species it could be: convexum, frosti, orientale, and pothos. The species are often sexually dimorphic in color (males often with a black abdomen) and/or elytral length (only females with long elytra or sometimes both sexes, but sometimes the female's are longer).

They are indeed pollen feeders as adults. Based on European work, the species seem not to be specific to particular species or even genera of plants. As you probably had the chance to see, the adults also use flowers as meeting and mating locations - I've collected and photographed a lot of those in New Hampshire! The larvae are found in leaf litter, moss, etc., and are probably predaceous like most omaliines.

There's another omaliine genus, Pelecomalium (much larger than Eusphalerum), with one supposedly eastern species (laevicolle) that could turn up with Eusphalerum. It was described from Pennsylvania by LeConte but I've never collected it and am not sure I've ever seen specimens beyond the original one(s). I had a vauge memory of Don Chandler having collected it, though, and I see (checking just now) that it's in the UNH collection database. All the other Pelecomalium species are western, so before hearing of Don's record I had wondered if the type specimen(s) were mislabeled.

Margaret K. Thayer, Ph.D.
Associate Curator, Zoology and Head, Division of Insects
Field Museum of Natural History
http://www.fieldmuseum.org
Chicago IL

Moved from Beetles.

I collected some that look similar on blossoms. Are some Omaliines pollen or nectar feeders?

maybe genus Eusphalerum, some of which have elytra not abbreviated.