Identification, Images, & Information
For Insects, Spiders & Their Kin
For the United States & Canada
Purple Metallic Beetle - Plateumaris

Purple Metallic Beetle - Plateumaris
Thompson Falls, Sanders County, Montana, USA
May 13, 2007
Found on Wild Yellow Iris. Is this in genus Donacia?

Moved from Beetles.

Plateumaris, I guess.
. . . for criteria, read:

Donacia or Plateumaris
It could be Donacia or Plateumaris. Personnally, I can't say which one with this picture.