Stink Bug Identification Guide

Key Features

• Shield-shaped body (a "true bug" in the order Hemiptera), typically 1.2–1.7 cm (0.5–0.7 inches) long
• Body is broadest across the shoulders and tapers toward a somewhat pointed rear, giving the characteristic pentagon/shield silhouette shared by the whole family
• Coloring varies widely by species, including shades of green, brown, gray, or mottled patterns, and some species show bright warning colors like red or orange
• Piercing-sucking mouthparts folded beneath the head when not feeding, forming a thin, needle-like beak
• Six legs and long, segmented antennae; wings are held flat over the back at rest, with a triangular plate (scutellum) visible between the wing bases that is a hallmark of the group
• Can release a noticeable odor as a defensive response when handled or disturbed, produced by glands on the thorax

Where & When to Spot One

• Found in gardens, fields, woodland edges, and on a wide variety of plants, where they are often seen resting on leaves or stems, sometimes in small clusters
• Present across most temperate and subtropical regions worldwide, with many different species varying by continent and habitat type
• Most active from spring through fall, with populations often peaking in late summer as new generations mature
• Adults may seek sheltered spots such as under bark, leaf litter, or building crevices as temperatures cool in autumn, sometimes gathering in numbers

Similar Species

• Squash bugs are a similar shield shape but tend to be more elongated and uniformly dark brown/gray, without the broader "shoulders" of many stink bugs
• Leaf-footed bugs share the general body plan but often have flattened, leaf-like expansions on their hind legs, which true stink bugs lack
• Brown Marmorated Stink Bug is a specific species within this group, distinguished by its mottled brown pattern and banded antennae/legs (see its own guide for detail)
• Assassin bugs can share a similar general outline but usually have a narrower head and a more elongated, slender body compared to the broad shield of a true stink bug
• The shield/pentagon body outline combined with the triangular scutellum plate on the back is the most reliable way to recognize a stink bug as a group

Quick ID Checklist

• Shield/pentagon-shaped body
• Triangular scutellum plate visible on the back
• Color varies (green, brown, gray, mottled)
• Piercing-sucking mouthparts folded under the head
• Releases a noticeable odor when disturbed