330 MANUAL OF VEGETABLE-GARDEN INSECTS 



The beetle is about ^ inch in length, greenish black in color 

 with the prothorax yellow (Fig. 208). The insect hibernates 

 in the adult stage and appears in the field early in the spring. 

 The female deposits her elongate, elliptical, orange eggs, from 

 To to iV ii^^^h in length, on end, in clusters of about thirty on 

 the ground at the base of the plant. Each female may lay 

 several batches of eggs at intervals of a few days. The larva 

 escapes through a slit in the side of the egg near the base. The 

 young larva is nearly ^ inch in length, uniform light gray and 



armed w ith numerous black 

 spines which are white at 

 the tip. The young larvre 

 crawl to the plants and feed 

 on the underside of a leaf, 

 at first gnawing off only the 

 surface but later eating out 

 holes. When alarmed, the 

 larvae fall to the ground, 

 where they remain hidden 

 until the danger is past. 

 The young larvre have the 

 habit of feeding in colonies 

 but when older become scattered. After the tops are killed, 

 they may feed on the roots. The mature larva is a little more 

 than ^ inch in length, leaden gray, with head and mouth-parts 

 brownish. When feeding on beets, it acquires a purplish color. 

 The larva becomes full-grown in ten days to a month. It 

 then enters the ground and transforms to a grayish pupa in a 

 slight earthen cell near the surface. In six to nine days the 

 transformation to the adult takes place and after waiting a 

 day or two to become hardened the beetle emerges. At 

 Washington there are two generations annually. Egg-laying 

 by the new brood of beetles begins the latter part of July 

 and continues until September. 



Fig. 208. 



The spinach flea-beetle 

 (X 71). 



