Boisea trivittata is an American species of true bug, commonly known as the Box Elder Bug, or Maple Bug. It is found primarily on maple and ash trees. The adults are about 12½ mm (½ in) long with a dark brown or black coloration, relieved by red wing veins and markings on the abdomen. Nymphs and immature bugs are bright red.
These insects feed on the softer plant tissues, including leaves, flowers, and new twigs. Unless the population is exceptionally large, the damage to plants is minimal. During years when their population soars, they can damage useful shade trees.
In autumn, they can become household pests. The adult insects seek wintering hibernation locations and find their way into buildings through crevices. They remain inactive inside the walls (and behind siding) while the weather is cool. When the heating systems revive them, they begin to enter inhabited parts of the buildings. In the spring, the bugs leave their winter hibernation locations to lay eggs on maple or ash trees.
In late spring, groups of 50-200+ bugs may gather on house siding or brick, usually in a sunny spot. A month or two later you may find pairs of them mating, connected end to end, also in groups of 3 and 4.
These insects can be killed with a dilute mixture of soap and water — 2 tablespoons per gallon — sprayed on them directly. This procedure can stain or discolor siding however. Natural insecticides have also been proven to be very effective in killing these bugs and eliminates the possible damage to siding. A small strip of duct tape can also be an effective way of killing these insects, as they seldom will fly away when approached. Unable to escape from the adhesive backing, they can then be disposed of. They can also be kept out of the home, to a degree, by putting boric acid and/or diatomaceous earth in places they would gather to enter, as well as by using weather stripping and other means to seal the house better.
Another well proven technique is to spray them with streaming Wasp and Hornet insecticide. The aerosol cans allow you to surprise them from a distance, and will kill them instantly. Not all flying insect sprays will kill them, you should use the products specified for wasps. The best time to use this technique is when they are gathered in large groups in the Spring.
The boxelder bug is sometimes known as a garage beetle; the unscientific name "stink bug," more regularly applied to the family Pentatomidae, is sometimes used to refer to Boisea trivittata.
People who move to southern states often confuse this species with one or more of the scentless plant bugs, Jadera spp. The Box Elder Bug has 4 wing parts