340 INSECTS INJURIOUS TO THE RED CURRANT. 



are black or brownish black. The female is larger thau the 

 male, and differs in the color of its body, being mostly yellow 

 instead of black. These flies are active only during the 

 warmer parts of the day ; at other times they are quiet or 

 almost torpid. 



Within a few days the female deposits her eggs on the 

 under side of the leaves on the larger veins in rows, as 



shown in Fig. 353. 



Fig. 353. 



When first laid, they are about one- 

 thirtieth of an inch long, 

 but they either absorb 

 moisture from the leaf, 

 or else the expansion is 

 due to the development 

 of the enclosed larva, and 

 within four or five days 

 7 they increase in length 

 to about one-twentieth 

 of an inch, are rounded 

 at each end, whitish and 

 glossy. In about ten 

 days the young larva 

 hatches, and it is then 

 about one-twelfth of an 

 inch long, of a whitish color, with a large head, having a 

 dark, round spot on each side of it. At first they eat small 

 holes in the leaves, as shown at 2 and 3 in the figure, feeding 

 in companies of from twenty to forty on a leaf, so that soon 

 the leaf is completely destroyed, all its soft i)arts being con- 

 sumed, and nothing but the skeleton frame-work remaining. 

 Shortly they increase in size, and, parting company, spread in 

 all directions over the bush, first changing to a green color, 

 then to green with many black dots, and finally to plain green 

 again, tinged with yellow at the extremities, just before the 

 change to the chrysalis takes place. When from half to two- 

 thirds grown, they are extremely voracious, and will, when 

 numerous, often strip an entire bush of its leaves in the course 



