Box elder bugs are part of the stink bug family and can swarm buildings by the thousands!
Box elder bugs normally feed on the leaves, flowers, and seed pods of the boxelder tree or silver maple. Large numbers of box elder bugs are usually on the female, or pod-bearing, tree. These insects feed on male box elder trees and other trees and plants, but they usually do not build up to such large numbers. The adults search for a place to overwinter which brings them into houses where they hide in small cracks and crevices in walls, door and window casings, attics, and around the foundation. During warm days in winter and early spring they come out and scatter through the house. On warm days during winter and early spring, box elder bugs sometimes appear on light painted surfaces outdoors on the south and west sides of the house, resting in the sun.
Treatment for Box Elder Bugs can be tricky.
Treatment for these would include a repellent liquid spray to the areas they are infesting. If this is a seasonal issue for your home or business you should consider having a preventative treatment complete before the start of their masses. A good time to prevent spring invaders is actually treating during the fall just before it starts to cool down. This will repel them away from the structure when they go to look for a place to ride out the winter cold.