Drain Fly Larvae
Usually, the homeowner never sees drain fly larvae since the larvae are located in the gelatinous film inside drains. However, sometimes, when drains are taken apart, larvae can be found in the film.
Drain fly larvae are not longer than 4 to 10 mm when fully mature and they are slender with a dark strip on the “back” or dorsal area. Larvae do not have eyes, and they are legless. On one end of the larva, there is a dark breathing tube used to extend out of the film to obtain air.
After the larvae mature, they will pupate or rest until they emergence as adults. The adult is the only life stage usually observed. Drain flies, even though they live in filth, are not known to spread any disease to humans.