August, '211 LATHROP AND BLACK: WESTERN PEACH BORER 329 



va lies curled. The cell varies in size with the age of the larva which 

 constructs it. We have found these cells ranging in width from five 

 to twenty millimeters, and in length from eleven to twenty-five mill- 

 meters. 



This habit of constructing winter cells seems to be much more pro- 

 nounced in heavy, wet soils, than in more porous types. 



Spring Activities. With the approach of spring the larvae become 

 more active. Those which wintered in cells outside the trees resume 

 their places in the tunnels under the bark. The more mature larvae 

 soon spin cocoons in preparation for pupation. Cocoons were found 

 at Roseburg as early as April 22, but were not found in great numbers 

 imtil late May or early June. At Corvallis and the more northern 

 portions of the State, these activities are more delayed. 



Adults: Emergence, Feeding, Oviposition. During several years 

 of field observation at Corvallis we have found that moths begin to 

 emerge during the last week of June. The number of adults emerging 

 increases until late July. The last week in July shows a decline in 

 the numbers emerging. Living pupae have been collected in the field 

 at Corvallis as late as August 12. 



At Roseburg in 1919 moths began to emerge as early as June 18. 

 July marked the period of maximimi emergence. Moths emerged as 

 late as August 15 fr^m cocoons which had been placed in breeding 

 cages. 



We found that captive moths took readily — almost greedily — dis- 

 tilled water, and also a dilute sugar solution. In the case of females 

 such feeding seemed to stimulate oviposition. No attempts were made 

 to attract moths to bait solutions in the field. 



We have found that oviposition ordinarily takes place soon after 

 emergence. In the field, eggs are most frequently placed on the trunk 

 of the tree, but occasionally on the larger limbs. In a few instances, 

 females were observed to dep jsit eggs on the soil at the base of the tree. 

 Specimens in small cages show much less selection and the eggs are 

 deposited, on any part of the tree, including the leaves, and even on 

 the wire and cloth of the cage. 



Records were kept of the niimber of eggs deposited by females confin- 

 ed in small cages. Upon the death of each moth the body was dissect- 

 ed and the number of vmlaid eggs also recorded 



The results are shown in the following table: 



