Aquatic Larvae 



113 



which also serves as a breathing-organ. In certain 

 Dragon-fly grubs there are three elongate gills at the 



Fig. 72. — a. Larva of Gnat {Cii/e.v) ; b. pupa, magnified 10 times ; c. tail-seg- 

 ment of pupa, more highly magnified. From Howard, Bull. 4 (n.s.) Div. 

 Ent., U.S. Dept. Agr. 



tail end of the abdomen. Other dragon-fly grubs take 

 water into the hind-gut over whose walls run tracheal 



H 



