37 



parts. Wingless (female scale insects), with 

 two pairs of membranous wings (white 

 flies, leaf hopper, etc.), or with two pairs of 

 wings, the first of which is thickened at 

 the base and membranous at the tip, 

 beneath which the larger, membranous 

 second pair is folded (true bugs) 



... Order III, Hemiptera. 



(c) Large insects, conspicuous in the adult 

 condition, strong of flight. The larvae 

 are aquatic ... ... Order IV, Odonata. 



(c) Small insects, living in colonies and con- 

 structing nests and covered galleries, 

 winged adults appearing only at certain 

 periods (Termites) ; wingless parasites, 

 solitary in habit, living in the plumage of 

 birds, or in the fur of animals (the biting 

 lice) ; or minute insects, sometimes wing- 

 less, which are found in old books, papers, 

 etc. (the book lice) ... Order V, Platyptera. 



B. Insects winged. ... ... ... See (d) 



B. Insects wingless : Parasitic insects, with 



thin, flattened bodies and much-developed 



hindlegs adapted for leaping. 



Fleas ... Order IX, Diptera, 



(d) Insects with one pair of wings 



Order IX, Diptera. 



(d) Insects with two pairs of wings ... See (e) 



(e) Wings clothed with scales 



Order VII, Lepidoptera. 



(e) Wings not clothed with scales ... See (f) 



(f) Wings of the first pair thickened, 

 meeting in a straight line down the back, 

 forming a cover for those of the second 

 pair, which are membranous and folded 

 beneath ... ... Order VIII, Coleoptera. 



(f) Wings of both pairs membranous See (g) 



(g) Wings with many cross veins, larger in 

 proportion to size of the body 



Order VI, Xeuroptera 

 (g) Wings with few or no cross veins, small in 

 proportion to size of the body 



Order X, Hy menoptera. 



