278 



FRUIT INSECTS 



t^ 



Fig. 239. — Peach 

 branch with bark re- 

 moved to show the 

 burrows of the fruit- 

 tree bark-beetle. 



(Fig. 237). They emerge in early spring, 

 and the female immediately seeks out a 

 suitable branch in which to deposit her eggs. 

 Having selected the place, she burrows di- 

 rectly to the sapwood, and there partly in 

 the wood and partly in the bark constructs 

 an egg chamber which usually runs length- 

 wise of the branch and is from J to 2 inches 

 long (Fig. 238). From time to time as the 

 burrow advances she lays her minute, deli- 

 cate white eggs close together in a single 

 row on each side of the chamber, gluing 

 them in place with a gummy secretion. It 

 takes her not far from a week to complete 

 the egg chamber, and as the eggs hatch in 

 about three days those first laid hatch before 

 the last are deposited. On hatching, the 

 minute, whitish grubs start their burrows at 

 right angles to the egg chamber, but soon 

 change the direction, so that by the time 

 they are full-grown most of the burrows are 

 running lengthwise of the branch (Fig. 239). 

 The full-grown larvae are about y^g inch in 

 length, whitish in color, with brown mouth 

 parts; the anterior segments are consider- 

 ably enlarged, and the hind end of the body 

 is obtusely rounded. They become grown 

 in about 20 days, and then excavate a narrow 

 cavity in the sapwood about \ inch deep, 

 plug the opening with sawdust and trans- 

 form to pupae within (Fig. 241). In about 

 10 days the beetles gnaw their way to the 

 surface. The complete life cycle requires 

 from four to six weeks. The separate 



