64 



INJURIOUS AND USEFUL INSECTS 



is shuffled off downwards, like a stocking stripped off the 

 leg, the loose skin of the upper part of the body being passed 

 through the girdle. In order to provide room enough for 

 this, the spinning larva doubles up its body, throwing the 

 head far back, so as to give it a wide sweep. When once 

 the larval skin is cast, the pupa has only to lean back a little, 

 in order to get a comfortable support from its girdle. 



The cabbage whites illustrate the points of difference 



Fig. ^6. — Larva of large cabbage white. X 2. 



between a butterfly and a moth. In them, as in all butter- 

 flies, the wings are broad, erected over the back when at 

 rest, or fully expanded, but never folded fanwise, as often 

 happens in moths. The fore and hind wings are never secured 

 by a bristle and catch, as is the case with most moths. The 

 body is slender. The feelers are long, and thickened or 

 knobbed at the tip. Like other butterflies, the cabbage whites 

 fly by day, and usually only in sunshine. The pupa is fixed by the 



tail, and, as in some 

 other butterflies, 

 is further secured by 

 a silken girth. 



It is hard to find 

 a simple and effec- 

 tive remedy against 

 Washes and sprays produce 



Fig. 47. — Larva of small cabbage white. X 2, 



the larvae of the cabbage whites. 



little effect, for the larvae conceal themselves on 'the under 

 side of the leaves, or in the heart of the cabbage; and, 

 besides, there is a waxy bloom on a cabbage-leaf, which 

 throws off the liquid. It is possible, by patient search, to 

 remove the egg-clusters of the large cabbage white, but the 

 process is slow and troublesome; no one would dream of 

 hunting for the single eggs of the other two species. A 

 frequent change of crop will keep down the numbers of 



