GROWTH AND TRANSFORMATION 167 



(Fig. 43, d), in which the wing- rudiments are well-developed 

 and the cuticle is relatively firm, each last for ten days or a 

 fortnight. After its fifth moult the wings are fully developed 

 and the sucker assumes the adult form. 



Cicads are much larger insects than suckers or aphids ; 



Pig, 44. — Seventeen-year Cicad {Tihicina septendecim) , North 

 America, a, first-stage larva, X 20 ; b, fourth-stage larva, X 5 ; c, feniale, 

 natural size. After C. L. Marlatt (Entom. Bull. 71 , U.S.D.A. 1907). 



they form a prominent feature in the insect fauna of most 

 warm and tropical regions, but they are represented in 

 England by a single species, found only in the south, and 

 there but rarely. They have robust bodies, and broad 



