This is a fairly good sized (13-17mm) True Bug (Hemiptera), mostly black with an orange border along the wings and on 3 sides of the pronotum, and varying degrees of orange speckling amid the black. They are the only members of the family Largidae (Bordered Plant Bugs) in the PNW. Both adults and larvae are primarily plant eaters, but they will also eat dead insects and various animal’s feces. The larva have been found to eat eggs of their own species. Both nymphs and adults will periodically gather in large numbers, although the reason behind this behavior is not clear. Largus spp. seem to be unpalatable to some lizards, who, when offered nymphs of Largus californicus, “..attacked but immediately spit the bug out and wiped their mouths on the sand.“ (Booth, 1990) This is probably due to stored cardenolides acquired from plant hosts such as dogbane. They are not considered to be a pest species.
http://bugeric.blogspot.com/2014/05/livin-largus.html?m=1
https://bugguide.net/node/view/93845
Size- 13-17mm
Habitat- Various
Range- West of the Cascades
Eats- Plants, dead insects, feces; often feeds on cardenolide rich species of plants, like dogbane, which confers some resistance to predation, and may account for the somewhat aposematic (warning) coloring of these bugs.
Flight Season- Year around
How to kill this bugs, we have an infestation
Bummer! I’m not an exterminator so I have no idea what would be effective.