Lesson 5 - Page 2



The Family Chironomidae is referred to as non-biting midges because the adult mandibles (jaws) are poorly developed.  Larval chironomid species can help track ecological conditions.  This group can tolerate polluted water.  However, low numbers in  a diverse population can indicate non-polluted conditions.   

Dixa sp.


The Family Dixidae includes familiar non-biting midges that are small insects that swarm around a pond or stream at dusk.  Females deposit eggs in shallow water.  The larvae have distinct thoracic segments and are U-shaped at rest.  The pupa stage is not truly aquatic, as they attach themselves just above the water. 

The Family Culicidae are similar to mosquito but the adults do not bite (midges).  The larva are called phantom because they are transparent.  They have jerky, lashing movements of the body.  The larva is predatory and catches small crustacean and other larvae with their antennae.   

Phantom midges

The Order Ephemeroptera refers to small to medium terrestrial insect with incomplete metamorphism.  Its wings are delicate and held together at rest.  The have large compound eyes with a reduced mouth because the adult does not eat, as it lives for a few hours to a week.    The nymphs however are herbivores and browse on the substrate.  The nymphs have three occasionally two distinct cerci (tails).  Cerci may be fuzzy or thread-like.  Nymphs are climbers, bottom crawlers, or burrowers. 


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