What exactly is a chironomid?

I've seen the term and Googled it, but can't really get a firm grasp of exactly what a chironomid is. Can somebody clue me in?

Thanks.

from ym understanding it's just a small midge that is mostly found in lakes and a vital part of a stillwater trouts diet.

If you listen to the internet radio show "Askaboutflyfishin.com" Wed night at 6PM the guest is Brian Chan who is THE premier stillwater expert on the subject and I'm sure he will discuss chironomids as part of the show. It promises to be one of the best shows this year.

GD

it's a gnat pupa.

looks like a mosquito larva's child ( in laymans terms )