164 



LOCUSTS, BUTTERFLIES, BEES, WASPS 



become larger and larger until after the last molt they appear 

 fully developed (Fig. 102). Such a development — in 

 which the egg hatches into a form resembling the adult — 

 is Imown as a direct development, and insects ha\ang a 



Fjg. 102. — Nyniplis of a lofiist : A, first .stage ; B, .second stage ; C, third 

 stage ; D, foiirtl:i stage ; E, fiftli stage ; F, final stage. .A.fter Emerton. 



ilirect development are said to have an incomplete iiieta- 

 7i)0'r pilosis. 



Economic importance of the locusts. — Since locusts 

 persistently feed upon grasses, grains, and forage crops, 

 they are of consideralile ecdnomic importance, allhough the 

 ('.•ii-olina Idcust does not cause so much injury as some other 

 :jpecies. The Rocky Moimtain locust, t-ha.t in past years 



