What's the name of the bug that squirms in the water?

Chironomid larva

Chironomids belong to Chironomidae, and their larvae are not only natural food for many economic fish, but also indicators of water nutrition types, environmental monitoring and water quality evaluation, and also play a certain role in self-purification of sewage.

Therefore, the identification of chironomid larvae is of great significance for aquaculture, ecological environment protection and limnology theory research.

morphological character

Chironomid larvae consist of head and 13 segments, the first three segments are chest and the rest are abdomen. There are a pair of toe-hooked forelimbs at the end of the first thoracic segment and the last abdominal segment of the larva, which are called forelimbs and hind forelimbs respectively. There are 2 ~ 3 pairs of anus and gills between the hind forelimbs. Larvae's respiratory system is closed and valveless, and gas exchange is carried out in water through body walls (and gills).