What it looks like:
2-2.5 mm in length. Its body has wide, alternating bands of orange and dark brown with orange-brown legs. The elytra fully cover the abdomen and have striae, or shallow punctures, running the length of the wing coverings. There is only one other species of Heterlimnius in our area. H. corpulentus has ten antennal segments, while H. keobelei has eleven segments. However, beetles have been found with one ten-segmented antenna and one eleven-segmented antenna, calling into question just how distinct the two species really are from one another.
Where you'll find it: These beetles can be found in rapid streams at high elevations from British Columbia down into the northern Sierra Nevada.
Natural History: Very little is known about the habits of H. corpulentus. However, it appears they are rarely found in streams below 6,000 feet.