THE PEACH-TREE BARKBEETLE. 



99 



THE EGG. 



The eo-o-s of the first generation may be found about the third week 

 in April, and, from that time on, the eggs of the first and second gen- 

 eration can not be separated, owing to the irregular emergence of 

 beetles and the irregular forming of egg burrows. Eggs can be found 

 in all stages of development up to the first week in October. The 

 eggs of the second generation begin to appear about August 1. 

 ^Owing to the small series of eggs observed, the following data on 

 lenoth of the egg stage are not given as conclusive : Eggs of the first 

 generation require from 

 IT to 20 days to hatch, 

 wdiile the eggs of the 

 second generation hatch 

 in about 8 to 10 days. 

 The egg (fig. 20, ^0 is 

 milky white when first 

 deposited, being ellip- 

 tical in shape, opaque, 

 and measuring 0.06 mm. 

 in length by 0.0885 mm. 

 in diameter. The egg- 

 shell is fairly tough and 

 the eggs ma}^ be very 

 easily taken out of the 

 egg cells. "When work- 

 ing without interruption 

 the female deposits from 

 2 to 10 eggs each day. 

 in addition to making 

 the cells. 



The number of eggs 

 in egg burrows of this 

 species varies, since the 

 eggs are not always de- 

 posited at equal intervals. Each brood chamber may contain between 

 80 and 160 eggs. In the vicinity of Lakeside, Ohio, eggs can be found 

 from April 20 until October 1. The egg burrow is not always made 

 next to the sapwood, as in a tree where the bark is very thick the 

 chambers are formed in the latter about one-fourth of an inch from 

 its outer edge. 



THE LARVA. 



\V\\eu tlie embryonic larva has become fully developed it lies in 

 a curved position in the shell. After moving about a short time 



Fig. 20. — The peach-tree barkbeetle (I'liluotribus Uini- 

 nuris) : a, b, Adult, dorsal and lateral views; c, egg; 

 (I, larva; c. pupa. (Jreatly enlarged. (Original.) 



