10 



MANUAL OF VEGETABLE-GARDEN INSECTS 



Fig. 10. — Cocoon of the 

 cabbage looper from 

 which the moth has 

 emerged ( X f ) . 



When mature the caterpillar spins a light flimsy semi- 

 transparent cocoon (Fig. 10) of white silk about Ij inches in 

 length, usually on the underside of the leaf. It consists of 

 two filmy layers, an inner one close to 

 the pupa and an outer one connected 

 with the other by many fine threads. 

 vSoon after completing its cocoon, the 

 larva transforms to a dark brown or 

 blackish pupa (Fig. 11) about f inch 

 in length. The moth (Fig. 12) emerges 

 in ten days to two weeks; it has an 

 expanse of Ij to 1| inches. The front 

 wings are dark brown variegated with 

 lighter brown and bear near the center 

 two silver spots, one oval and the other shaped like a con- 

 stricted U. Sometimes these spots are united and resemble 

 an imperfect figure 8. The hind wings are mouse-colored 

 with bronze reflections in certain lights. 



There are said to be three broods of the insect annually on 

 Long Island, New York, and four at Washington, D. C. As 

 only a relatively small number 

 of pupa? survive the winter, the 

 first brood caterpillars are gen- 

 erally not abundant enough to 

 cause much injury and are 

 usually overlooked entirely. 

 The succeeding broods increase 

 rapidly in numbers and impor- 

 tance, the last being the most 

 destructive. Towards the end 

 of the season, the broods over- 

 lap so that all stages of the insect are present on the cabbage 

 plants at the same time. 



The cabbage looper is held in check by several parasites and 



Fig. 11. 



— Pupse of the cabbage 

 hwper (X 21). 



