THE PEACH-TREE BARKBEETLE. 



97 



of the egg burrow. While an extension opposite this is being made 

 the males copulate with the females at this point. At other times 

 the males remain between the mouth of the burrow and this niche, 

 occasionally going deeper into the burrow. Copulation ordinarily 

 takes place at the fork in the burrow, and has been observed a number 

 of times to last as long as fifteen minutes after the cutting aAvay of 

 the bark. The female rests with the posterior end of the abdomen 

 just at the edge of the fork, the male operating from the adjoining 

 niche. The sole function of the male seems to be that of attending 

 the female, as none has ever been observed working. 



The forks of the burrow may or may not be nearly equal in length, 

 but usually they vary to quite an extent. They are, however, always 

 more or less horizontal, 

 running around the axis ..illllliJllllliliillilililM.llliiiilillPlllllllllllllllllllliiiiilinJ 



of the limb. (See figs. 18 

 and 19.) After being fer- 

 tilized the female imme- 

 diately sets about deposit- 

 ing eggs, and at this time 

 the abdomen is very much 

 swollen. During the con- 

 struction of the burrow 

 copulation occurs several 

 times, so that the length 

 of the burrow appears to 

 depend upon the num- 

 ber of times of copulation. 

 As soon as the egg is de- 

 posited the female covers 

 it with frass, so that the 

 main burrow is a circular 

 tube of sawdust, outside of which occur the eggs. The method of 

 egg deposition is as folloAvs: 



Having made the egg cell, the female backs out to the niche where, 

 after turning around, she backs into the cell again, clinging to the 

 side of the burrow. The egg is then placed in the cell, and after 

 again turning around the female covers it with the sawdustlike frass. 

 The egg cells aie filled as soon as the}^ are fuiished, and each is made 

 as soon as the burrow has been extended far enough to make room 

 for it. 



From ten days to two weeks are necessar}^ for the completion of 

 the burrows. The males and females in the same burrow live until 

 after most of the larvw have developed into the next brood of beetles. 

 The completed burrows of this species are more nearly equal in length 



Fig. 19. — Work of the peach-tree barkbeetle {Pliloeo- 

 tribus liminaris) : Galleries in wood of peaeh tree, 

 May 18, 1908, Lakeside, Ohio. Enlar.ired. (Orig- 

 inal. I 



