Bug invasion.. what is this insect
Thank you for attaching the excellent images which made it easy to identify those little invaders. The insects are elm seed bugs, Arocatus melanocephalus. These insects are new to the US. They were first identified in Idaho. (“Imported elm seed bug found in southwest Idaho”: http://www.spokesman.com/stories/2012/jul/19/imported-elm-seed-bug-found-in-southwest-idaho/)
They have since spread widely through the northwest.
Elm seed bugs are considered nuisance pests because they feed primarily on elm seeds. Their activities are similar to box elder bugs which feed on box elder seeds. But late in the year, both are nuisance pests which congregate on the exterior walls of houses and other structures during the fall and, then, may migrate indoors. Unfortunately, elm seed bugs also invade structures during the spring and summer, when temperatures rise.Management tactics for all such nuisance insects is the same, with emphasis on pest-proofing homes in preference to using pesticides. Caulk and/or seal potential entrances indoors around windows, also repair and/or replace torn screens. If only a few bugs are present, flick them into soapy water; if they’re particularly numerous, a wet-dry shop-vac is useful. See “What’s Bugging You?”: http://ext100.wsu.edu/gardentips/2015/09/03/whats-bugging-you-2/