Dlptera . The true flies are one of the largest and most diverse 

 of the orders of insects. As is apparent by the name, its members are 

 typified by the presence of two wings. Ordinarily, Diptera develop through 

 complete metamorphasis, egg to larva to pupa to adiolt. Approximately 

 50 percent of this order have aquatic stages in their life cycle, and 

 many of these are important fish- food organisms. 



Tanyderidae . A most \inusual larva was discovered dxiring the 

 course of the survey. At mile 229.8 the larva of Protanyderus sp., the 

 immature stages of which have never previotisly been reported, were foxuid 

 with great regularity. A diligent, but unsuccessful, effort was made 

 to locate the pupal form. This is sm archaic or prototype crane-fly, 

 the larvae of which are similar to those of Protoplasa fitchii , the only 

 previously recorded larva in this rare family. Protanyderus is charac- 

 terized by a fully sclerotized head capsule, long prolegs with retractable 

 claws at the posterior end only, but most striking are the six long fila- 

 ments at the ca\idal end of the body. In February I96I, one of these larvae 

 was collected that appeared to be conmencing pupation. Unfortunately, 

 high flows in the river the succeeding two months did not permit sampling 

 at this station. By April only relatively small individuals were present. 



Tipulidae . Most of the crane flies are semi-aquatic or terres- 

 trial in their immature stages, but a few such as Antocha and Hexatoma 

 sure strictly aquatic . Only a single genxis ( Antocha ) of this family was 

 collected with any degree of regxilarity, and the pupa of this animal is 

 different from any previovisly described in that the first branch of the 

 respiratory organ is swollen and curves around to the front rather than 

 pointing upward. Johannsen (l93'<-) reports that members of this genus 

 construct laiveLL ceuses. No silken lsu:val cases were discovered in this 



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