four-humped stink bug

not listed

NNR - Unranked

not listed

Four-humped stink bug is a common and widespread, medium-sized, stink bug. It occurs in the United States, Mexico, and southern Canada. It is most common in the eastern United States and adjacent Canadian provinces. It is uncommon in Minnesota.

The female is 9⁄16″ to ¾″ (14.6 to 18.6 mm) in length. The male is smaller, ½″ to ⅝″ (12.4 to 16.0 mm) in length. The body is narrowly oval to elliptical, somewhat shield-shaped in outline, and somewhat flattened. It is mottled dark brown to brownish-gray, often with areas of red, orange, or white. It has many large, irregularly scattered, black pits, and is densely covered with numerous small, gray-bordered pits (punctate). The overall effect is a camouflaged, bark-like appearance

The head is small and narrow, much narrower than the thorax. It is tucked into a concave groove in the margin of the pronotum. There is no visible “neck” when viewed from above. The sides of the head are concave. There are two large, bulging, compound eyes and two small simple eyes (ocelli). There is no crosswise (transverse) groove between the compound eyes. The front of the head is divided into a central lobe (tylus) and two lateral lobes (juga). The juga are much longer than the tylus but converge toward the end and sometimes overlap. When the juga do not overlap, the sinus between them is deep and narrow, and the sides are not parallel. When they do overlap, the head does not appear notched at the tip. Each jugum has a single conspicuous tooth on the side (subapical tooth) between the compound eye and the tip, nearer to the tip. The subapical tooth has straight sides and forms a right angle at the tip. The mouth parts are optimized for piercing and sucking, and take the form of a thick, curved, 3-segmented beak (rostrum). The rostrum is longer than the head and fits into a groove on the underside (sternum) when not in use. The antennae have five segments. They are brownish-black, slender, and long, much longer than the head but not as long as the body. The first segment is sometimes reddish. The third segment is one and a half times longer than the second.

The thorax is twice as wide as long. The exoskeletal plate covering the thorax (pronotum) is coarsely and irregularly pitted. The lateral margins have 5 to 10 triangular teeth. The shoulder (humeral) areas, above the wing bases, are distinctly swollen. The front corners (humeral angles) jut outward with a nearly square but with rounded corners (subquadrate) projection.

There are two pairs of wings, and they are held flat over the body when at rest. Between the wing bases there is a large plate (scutellum). The basal portion of the scutellum is broadly triangular and distinctly elevated. The lower portion is U-shaped and extends nearly to the tip of the abdomen. The basal corners are swollen. The swollen corners, along with the swollen humeral areas on the pronotum, may be the four “humps” that give this bug its common name. However, I can find no detailed description that includes the source of the name.

The forewings (hemelytra) are as long as the abdomen but do not completely cover the sides of the abdomen. The sides of the abdomen are exposed and are conspicuously striped with black and grayish-brown. The grayish-brown stripes are usually partly reddish, orangish, or whitish. The hemelytra have a thickened, leathery section at the base and a thin membranous section at the tip with a clear dividing line between the two. The thickened basal part is comprised of a narrow area (clavus) behind the scutellum when the wings are closed, and the remaining broad marginal area (corium). The membrane is dark brown with a brown and white pattern between the veins.

The legs are striped with alternating broad black stripes and narrow reddish, orangish, or whitish stripes. The fourth segment (tibia) of the hind legs has hairs but no spines. The last part of each leg (tarsus), corresponding to the foot, has three segments.

Female: 9⁄16″ to ¾″ (14.6 to 18.6 mm)

Male: ½″ to ⅝″ (12.4 to 16.0 mm)

April to October (CCESR)

Adults overwinter in leaf and plant litter. In the spring, the female lays clusters of barrel-shaped eggs in tight rows on the underside of leaves.

A wide variety of plants from at least eighteen plant families

Sources

24, 27, 29, 30, 82, 83.

Location: Just west of Houston, MN