Demodex species are parasitic mites that are commonly found on humans, residing in hair follicles (Demodex folliculorum) and sebaceous glands (D. brevis). They do not cause symptoms in most people. The adult mites are microscopic, measuring only 0.3 to 0.4 millimeters long, with D. folliculorum being longer than D. brevis. They have a semi-transparent body with 8 short legs (arrow) coming off of the first body segment.