12 Key to Families of North American Insects. 



71. Small degraded forms bearing little superficial resemblance to insects, ^ith a 



long slender beak, and usually covered with a waxy scale or powder or cot- 

 tony tufts; living on various plants. Scale insects 



HOMOPTERA (Page 73) 



Body quiescent, but able to bend from side to side; not capable of feeding, 



enclosed in a skin which is tightly drawn over all the members, or which 



leaves the limbs free but folded against the bodj^; sometimes free, sometimes 



enclosed in a cocoon or in a shell formed from the dried larval skin 72 



72. The skin encasing the legs, wings, etc., holding the members tightly against the 



body; prothorax small; a proboscis showing 73 



Legs, wings, etc., more or less free from the body; biting mouthparts show- 

 ing 74 



73. Proboscis long; four wing-cases; sometimes in a cocoon. .Pupse of Lepidoptera 

 Proboscis short; two wing-cases Pupae of Diptera 



74. Prothorax small, fused into one piece with the mesothorax; sometimes enclosed 



in a loose cocoon Pupse of Hymenoptera 



Prothorax larger and not closely fused with the mesothorax 75 



75. Wing-cases with few or no veins Pupse of Coleoptera 



Wing-cases with a number of veins Pupae of Neuropteroid Orders 



