What's this insect (Oregon, USA)?
Your picture most likely shows Lichnanthe rathvoni of the family Glaphyridae.



The older answer is almost certainly not correct in any of its guesses; all of the possibilities listed are Palaearctic (see the sites https://fr.wikipedia.org/wiki/Epicometis_hirta, https://en.wikipedia.org/wiki/Tropinota_squalida, and http://www.coleo-net.de/coleo/texte/oxythyrea.htm for confirmation; the first and third will need translating for those not fluent in French and German, respectively).

Referring to Part V of M. H. Hatch, The Beetles of the Pacific Northwest (1971) (which covers the states of Idaho, Oregon, and Washington, and the province of British Columbia, in their entirety, and the western part of the state of Montana), and assuming the subfamily Cetoniinae is correct, I had thought this was Trichiotinus assimilis Kirby; there are inconsistencies between this photo and those provided by bugguide.net (see http://bugguide.net/node/view/22486); specifically, the elytra here are well-separated apically, and the coloration is quite different.  A review of Volume 2 of American Beetles showed me my error: the insect is a member of the family Glaphyridae (formerly a subfamily of Scarabaeidae), and the genus Lichnanthe; returning to Hatch, 1971 shows only L. rathvoni LeConte from the covered area; photos of that species in bugguide.net (see  http://bugguide.net/node/view/115846) show some variation in markings from the photo here (which is to be expected), but are structurally fairly close.

The genus Lichnanthe was most recently revised in the following paper:

Carlson, David C..  1980.  Taxonomic revision of Lichnanthe Burmeister (Coleoptera: Scarabaeidae).  Coleopterists Bulletin, 34(2):177-208. 

which is available through JSTOR (a subscription, one-time payment, or access through a university will be needed).