Box Elder bugs are “true bugs”–in the order hemiptera, not beetles which are the order coleoptera.
They are black in color with a red orange banding around the margins front wings and red eyes. They are approximately 1/2″ in length as adults.
These bugs use their piercing-sucking mouth parts to eat young foliage of Box Elder trees in the spring but do not damage to the trees, mostly they eat the seeds of the Box Elder Tree, which although it doesn’t look like it, it is a maple tree. They also eat the seeds of silver maple trees. (You can too, they are quite tasty. Just a fun fact in case there is an zombie apocalypse.) You probably noticed Box Elder and Norway Maple and Silver Maple grow like weeds. They grow in hedges, lawns, you gutters. They are nuisance trees. The Box Elder bug is doing good work eating the seeds.
Its been a great year for these bugs here in the Berkshires! That means there are lots of them around. Even the larva are hibernating this year. Usually I get calls from north and south county with concerns of infestations, this year its the whole county.
They like to congregate on the south sides of house in the fall sometimes in the thousands. Also they congregate in trees where they naturally hibernate under the bark and cracks. In insects this state of hibernation is called “diapause”. Its not a true hibernation, they will come out on warm days and walk around. But they don’t eat, or mate or lay eggs. They just wander around, maybe drink some water, then go back to sleep. They sleep a lot to conserve energy.
They will NOT harm your house. They will not make piles of frass (insect poop) in your house as Orkin might try and tell you. They pretty much disappear in the cracks and crevices until spring, then they come out with the young leaves and seeds and start the life cycle again.
If these insects do become a nuisance in your house year after year, the solution is to cut down the tree.