Boisea rubrolineata (Western Boxelder Bug)

Another common true bug (Hemiptera) that is very common in the fall on, around, and in our homes, is the Western Boxelder Bug. They are multi brooded and in mid summer one could find all of their stages from egg to adult in a given location. But it is primarily late instar nymphs and adults that one finds seeking shelter in human abodes at this time. 

Boisea rubrolineata are brown and black  bugs with a crisp pattern of red veins on the leathery part of the wings, and a red border and midline on the pronotum. Similar shaped and colored insects, in particular Boisea trivittata, have black veins on the wings. 

Western Boxelder Bugs are utterly harmless creatures that feed primarily upon Big-leaf Maples (Acer macrophyllum) in their natural habitat, but will feed on a variety of maples, ash, soapberry, and even roses, in anthropogenic habitats. But the damage they do is slight. Some people do find them to be an irritant when they invade our homes in droves, but they are merely seeking shelter and will not damage household plants or lay eggs indoors. Vacuuming them up is an option, but a better one, if these creatures really bother you, is to seal your home against them, and hand catch and remove the invaders you find. 

https://bugguide.net/node/view/15578

http://www.soapberrybug.org/01_cms/details.asp?ID=56

https://www.extension.uidaho.edu/publishing/pdf/CIS/CIS1155.pdf

Size- Length 9-13mm

Habitat- Usually where maples are present

Range- Region wide except for high elevations

Eats- Prefers Big-leaf Maple both as a larval host and adult food source

Flight Season- Can be found year around, but not active during the coldest months.