HOW TO KNOW THE IMMATURE INSECTS 



3b. Antennae more slender longer than head; thorax not exceptionally 

 large. Fig. 122 Family SMINTHURIDAE 



The family is composed of about 

 200 species. These springtails are 

 very active and often occur in im- 

 mense numbers in moist places on 

 the surface of the soil or water. The 

 head is vertical and the antennae 

 inserted on the back portion of the 

 head. Various species of living plants 



Fig. 122. Sminthurides lepus constitute their food. 



Mills. 



ORDER PLECOPTERA 



(This key is compiled from Claassen and Prison.) 

 la. Gills present on first 2 or 3 abdominal segments. 



Fig. 123 Family PTERONARCIDAE 



The naiads of this family are all herbivorous. They 

 live in the small upland spring brooks and are un- 

 able to move rapidly, getting around awkwardly. 

 Upon being taken out of the water, they curl up. re- 

 maining motionless for some time. 



Fig. 123. Pteronar- 

 cella badia Hagen. 



lb. Gills absent on first 2 or 3 abdominal segments 2 



2a. Venter of thorax covered with large over-lapping shield-like plates. 

 Fig. 124 SubfamUy PELTOPERLINAE, PERLIDAE 



The single genus Peltoperla 

 is distributed over the Eastern, 

 Southern and Western United 

 States. The naiads are her- 

 bivorous and can be distin- 

 guished from other families by 

 the large shield-like pro-, meso- 

 and metanotum, short abdo- 

 men, wide legs, short cerci and 

 head bent under the body. 



Fig. 124. a, Peltoperlo arcuola Ndm 

 Ventral aspect of thorax. 



59 



