Forest stream beetles. Formerly placed in the Ptilodactylidae. One North American species, Stenocolus scutellaris LeConte (pictured). Adults emerge in summer and are found primarily on the branches of riparian trees. Females black, generally larger than males, which tend to be brown or grey; body covered with short, thick setae which may rub off easily; antennae 11-segmented and serrate in males, subserrate in females; scutellum round and covered with prominent white setae.

Larvae found in riffles, particularly under larger rocks and embedded wood. Elongate and large, female larvae up to 50 mm, male larvae smaller; nine distinct abdominal segments; urogomphi present, rigid and slightly upturned; abdominal segments 1-7 with paired, multi-branched filamentous gills.