86 



undeveloped, and moths where the females are wingless. It 

 would be impossible within the limits of the available space, 

 to adapt the key to include adequate reference to the excep- 

 tional cases, but this will not interfere with its usefulness in 

 connexion with the more common forms. 



The characters by means of which insects may be dis- 

 tinguished from ticks are chiefly the absence of wings, and 

 the possession of four pairs of legs, in the case of the ticks, 

 while the adult insect is, normally, winged and provided with 

 only three pairs of legs. (See also p. 5.) 



KEY. 



Insects with incomplete "metamorphosis, the life- 

 cycle consisting of three distinct stages of de- 

 velopment, egg, larva (or nymph), and (imago). 

 There is no quiescent pupal stage, during 

 which the wings and other organs characteris- 

 tic of the adult are developed See A. 



Insects with complete metamorphosis, the life- 

 cycle consisting of four distinct stages : egg, 

 larva, pupa and adult (imago.) The pupa is a" 

 distinctly quiescent stage during which occurs 

 the complete transformation from the grub, 

 maggot, or caterpillar to the winged, sexually 

 perfect adult See B. 



A. Insects with biting mouth parts . . . See (a) 

 A. Insects with piercing and sucking mouth 



parts See(b) 



(a) The first pair of wings somewhat thick- 

 ened and horny, serving as covers for 

 the membranous second pair, which are 

 larger and fold longitudinally, like a 

 fan ... Order I, Orthoptera. 



(a) Two pairs of membranous wings similar 

 in size, shape and structure, the second 

 pair sometimes larger than the first. The 

 wings do not fold See (c) 



(b) Small to minute insects, with fringed 

 wings, living entirely on plants and within 

 flowers . . ... Order II, Thysanoptera. 



(b) Small to moderate-sized insects ; generally 

 with a distinct proboscis, or sucking mouth 



