LIFE HISTORY OF THE GIPSY MOTH. 



15 



The white pine, as well as the spruce and the hemlock, is unable to 

 survive after one complete defoUation, and when only partially de- 

 nuded the trees are usually attacked by bark borers and other insects 

 so that death soon follows. The proper treatment of conifers to pre- 

 vent injury by the gipsy moth will be described farther on in this 

 report. 



THE PUP^ . 



(PL I, figs. 3, 4.) 



After the caterpiUars have finished feeding they usually select more 

 or less protected places in which to pupate. Stone walls, rubbish 

 piles, and open spaces beneath porches or outbuildings furnish excel- 

 lent places for caterpillars to enter the pupal stage. Of course, a large 

 number remain on the trees, where they usually pupate on the under 

 side of the branches, beneath loose bark, or in holes and cavities, or 



Fig. 2. — Pine trees killed by the gipsy moth. (Original). 



descend to the base of the trees before transforming. Previous to 

 pupation the caterpillar spins a few threads of silk in order to attach 

 itself firmly. The body then shortens considerably and pupation is 

 accomplished by the integument of the segments behind the head 

 splitting dorsally and the whole larval skin is forced back to the end 

 of the body, the pupa remaining beneath the network of silk which 

 held the caterpillar in place. The pupa is dark reddish-broAvn, and 

 the body segments bear yellow hairs, which are arranged in groups. 

 From 7 to 17 days are spent in this stage before the moth emerges. 

 As a rule female pupae are much larger than those of males, but the 

 sex can always be determined by the structure of the last segment of 

 the abdomen. 



