Its body is white except for its head capsule, dorsal plates and urogomphi, which darken in color to black, brown, or reddish as it grows.

Dermestes ater further differs from the two other species in having a symmetrical pattern of light and dark pubescence on all abdominal sternites.

[2] Larvae of D. ater can be distinguished from close relatives in having their urogomphi backwardly directed, but appearing nearly straight in side view.

Each tibia bears a short stout spine on dorsal apex of posterior face.

Abdominal tergites 4-9 without retrorse tubercles but instead each has a row of about 30 short erect setae immediately posterior to anterior transverse ridge (larvae of other species have much fewer than 30).

[4] It is an occasional predator, feeding on live insects; it is a pest of the sericulture industry because it preys on silkworm pupae, damaging the silk cocoons in the process.

[5] It also feeds on housefly (Musca domestica) larvae and pupae in places where both insects congregate, such as poultry houses.