Insect Lookalikes

The brown marmorated stink bug and the western conifer seed bug look very similar. How can I identify them correctly?

Why they are misidentified?

Both bugs are brown in color, have long antennae, and will try to get into houses in autumn to wait out the winter.

Brown Marmorated Stink Bug

The brown marmorated stink bug adult is about ¾ inch in length and almost as wide as it is long. The antennae are narrowly banded with off-white at the beginning and end of the segments. The legs are also banded, but sometimes the banding is yellowish brown and difficult to see. The head and the area behind the head have small bluish or copper-colored indentations. The overall color of this bug is dark brown.

Most often spotted: can be seen most anywhere, but are commonly found near agricultural settings like vegetable, fruit, and field crops.

Western Conifer Seed Bug

The western conifer seed bug is reddish brown, also about ¾ inch in length, but the width is only a third of the overall length. The long antennae and legs are not banded. The hind leg is flattened, expanded, and resembles a small leaf. Another identifying characteristic is a cross-hatching of thin white lines on the back.


Most often spotted: seen near conifer trees (they feed on conifer seeds)

Steve Jacobs

Steve Jacobs is an urban entomologist and senior extension associate with Penn State Extension.