44 Key to Families of North American Insects. 



ORDER PLECOPTERA. 



(PERLARIA.) 



Body soft, of moderate to large size; four membranous wings, 

 usually with many veins, anal area of hind wings large and pleated, 

 rarely with the wings greatly reduced in size; antennae long, thread- 

 like. Larvae aquatic, metamorphosis slight. Stoneflies, Salmon- 

 flies. 



(Pteronarcys, Perla, Chloroperla, Nemoura) (PI. 8, figs. 180, 182). 



PERLIDjE 



ORDER MEGALOPTERA. 



Soft-bodied species with large wings, long and sometimes pec- 

 tinate antennae and simple similar legs. Costal cell with many 

 transverse veins, subcosta and radius simple, the radial sector 

 arising near the base, anal space of hind wings large, folded fan- 

 like when at rest; pro thorax quadrate. Larvae aquatic, predatory, 

 with lateral abdominal gill -filaments; wings appearing during the 

 resting nymphal stage. 



Accessory veins at the end of the radial sector extending anteriorly; ocelli want- 

 ing; fourth tarsal joint prominently lobed on each side. (Sialis.) 



SIALIDIIXE 



Accessory veins of the radial sector extending posteriorly; three ocelli present; 

 fourth tarsal joint scarcely bilobed. (Corydalis [C. cornuta, Dobson, Hell- 

 grammite], Chauliddes) (PI. 8, figs. 179, 186) CORYDALID^ 



ORDER RAPHIDIOIDEA. 



(EMMENOGNATHA, part) 



Moderate-sized, slender, predatory species with elongate cylin- 

 drical prothorax; head large, nearly horizontal, mandibles strong, 

 antennae long and thread-like; wings membranous; both pairs 

 similar, with numerous forkings, the costal cell with crossveins; 

 legs similar, the first pair attached at base of prothorax, tarsi 

 five-jointed; cerci not developed. Metamorphosis complete. 



(Raphidia, Inocellia) (PI. 8, fig. 185.) RAPHTDIID^ 



