THE PEACH-TEEE BAKKBEETLE. 



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 burroAv. Copulation ^ordinarily 

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

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

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

 just at the edge of the fork, the male oi:)erating 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 cpiite an extent. They ai'e. however, always 

 more or less horizontal, 

 running around the axis 

 of the limb. (See figs. 18 

 and 10.) After being fer- 

 tilized the female imme- 

 diately sets about deposit- 

 ing eggs, and at this time 

 the abdomen is ver}' 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 e<i;g is de- 

 posited the female covers 

 it Avith frass, so that the 

 main burroAv is a circular 



tube of sawdust, outside of wdiich occur the eggs, 

 egg deposition is as follows: 



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 tlie burrow. The vg^ is then placed in the cell, and after 

 again turning around the female coA'ers it with the saAvdustlike frass. 

 The egg cells are lilled as soon as thej^ are finished, and each is made 

 as soon as the bui-row has been extended far enough to make room 

 for it. 



From ten days to two weeks are necessarj'- for the completion of 

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

 after most of the larva' have developed into the next brood of l)ee(les. 

 The completed burrows of this species are more nearly e<iual in length 



Fig. 19. — Work of the peach-tree barkbeetlc (Plilceo- 

 trihus Uminaris) : Galleries in wood of poacli tree, 

 May 18, 1908, Lakeside, Ohio. Enlarsed. (Orig- 

 inal. I 



The method of 



