HOW TO KNOW THE IMMATURE INSECTS 

 6a. Eyes dorsal; body distinctly flattened 7 



6b. Eyes lateral; body more or less cylindrical 8 



7a. Caudal filaments shorter than abdomen; 1st pair of gills inserted 

 on the ventral side of 1st abdominal segment. 

 Fig. 136 Family OLIGONEURIELLIDAE 



The body is more or less cylindrical with small 

 and short gills. Long hairs may be present on the 

 fore legs. 



Fig. 136. Ohgoneuria sp 



7b. Caudal filaments longer than abdomen; 1st pair of gills inserted 

 on the lateral sides of 1st abdominal segment. 

 Fig. 137 Family ECDYURIIDAE 



The naiads live in rapid waters, clinging to stones 

 and other objects, where the waves break over lake 

 shores and on the margins of gently flowing streams. 

 The body and appendages are flattened, the head 

 large and the gills leaf-like. 



Fig. 137. Hepta- 

 genia sp. 



8a. Abdominal gills inserted dorsally 9 



8b. Abdominal gills inserted laterally. 



64 



10 



