Boxelder bugs are black, winged insects that have 3 red stripes running lengthwise down their body, and a bright red color under their wings. Immature box elder bugs—or nymphs—are wingless, smaller, more round-shaped, and bright red in color. Box elder bugs are commonly found on elm, maple and boxelder trees. They are also commonly found congregating on houses and structures, typically on the south side during warm days. Boxelder bugs will typically appear during the winter in cracks and crevices in and around buildings, door and window frames, behind siding and soffits, tree holds, woodpiles, etc.