Chironomids
"Learn why the Chironomid pupal stage is most important."
aka: midges, mosquitoes, gnats
Family – Chironomus or Chaoborus, Order – Diptera
Etymology :
I believe chironomus is from the Greek cairw (chairo) meaning happy and nomos ( nomos) – meaning roaming or wandering, hence, it is a happy-wanderer at least until he is inhaled by a passing trout.
Diptera: also from the Greek meaning di = two and ptera = wings: as in pterodactyl or helicopter.
Entomology:
Larvae: In the early stage of a chironomids life cycle, the larvae are microscopic and wormlike with a many-segmented body. They build larval cases made of mud or a jelly-like substance and feed actively on algae and decaying vegetable matter. As they develop the larvae can grow anywhere from ¼ inch to over 1 inch in length before pupating, depending on the species. The red colour is what gives them the name Bloodworm.
Pupae: The pupal stage is the most important from a fly fishing perspective as the trout feed voraciously on these small emerging insects. The pupae range in size from ¼ inch to over 1 inch and most common colours being red, black, green, and tan depending on 
the aquatic environment. The pupa emerges from the larval case or tube and rises directly to the surface in a vertical migratory path. Once it reaches the surface, the head splits open and a tiny mosquito-like fly emerges.
Chironomid Fishing :
When chironomid fishing, many fly fishers use a floating line with a strike indicator and a leader anywhere from three to 20 feet long depending on the depth you are fishing. In order to get the chironomid to the desired depth, adjust your strike indicator to the length of leader and use bead head or split shot to facilitate sinking.
Of course a strike indicator is not always necessary. Many fly fisherman use a technique called ‘going naked' where they use only a weighted chironomid attached to a leader and floating fly line. Cast your line then allow it to sink to the desired depth. Begin a slow ‘figure eight' retrieve – pause – then continue. If fishing from a float tube I will often just give a little kick, causing it to rise slightly, and more often than not, will elicit a strike.
I
f you are targeting fish that are feeding at a depth greater than 20 feet a type II full sink line and a shorter leader is recommended. Fish it slow, often taking many minutes to retrieve a cast.
This chironomid is a little worn after catching a half dozen trout on local lake.