508 



COLEOPTERA. 



days from the time the larva ceases eating the oeetle appeared. 

 It then feeds on the seed leaves of cabbages and turnips and 

 other garden vegetables, when it proves very injurious, 

 while afterwards in June, when the plants have at- 

 tained their growth, they sicken and die from the 

 attacks of the larva in their roots. (American 

 Naturalist, vol. ii, p. 514.) 

 The Silk-weed Labidomera, L. trimaculata Fabr. (Fig. 505, 

 larva) is found in its larval stage on the Silk-weed about the 

 first of August. It is a thick hemispherical beetle, with a dark 

 blue head and prothorax, and orange elytra, with three large 

 blue spots on each wing-cover. It is one-half of an inch long. 



Fig. 505. 



c '^f f d 



Fig. 506. 



The Colorado potato beetle, Doryphora decem-Uneata Say 

 (Fig. 506 ; a, eggs ; b, the larvae in different stages of growth ; 

 c, the pupa ; d, beetle ; e, elytron, magnified ; /, leg, magnified) 

 has gradually spread eastward as f.ir as Maine, from its 

 original habitat in Colorado, having become very destructive 

 to tiie potato-vine. It becomes a beetle within a month after 

 hatching from the yellowish eggs ; the larva is pale yellow 

 with a reddish tinge and a lateral row of black dots. Messrs. 

 Walsh and Riley state that '^ there are three broods of larva? 

 every jxar in North Illinois and Central Missouri, each of 

 which goes under ground to pass into the pupa state, the first 

 two broods comiua: out of the oround in the beetle state about 



