96 



DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 



With the first warm weather iii spring — as early as the last of March 

 in the latitude of Lakeside, Ohio — the beetles begin cutting their way 

 out from their hibernation cells. They do not immediately leave these, 

 but remain from four days to a week or more, most of them feeding 



for a while and then migrating to trees, 

 wood piles, and brush heaps, or to any- 

 thing upon which they can feed and in 

 which make brood chambers. 



THE ADULT. 



HABITS. 



The beetles fly but little during the 

 morning hours, migrating from tree to 

 tree for the most part between the hours 

 of noon and night. During the day the 

 beetles move about on the trees, the 

 females seeking places in which to bur- 

 row and the males searching for burrows 

 alread}' started in which the usually 

 accompanying male is lacking. After 

 nightfall flight and movement over the 

 tree cease. 



The male beetles probably commence 

 feeding as soon as they cut their way 

 out of the pupal cell, and continue to 

 feed more or less as long as they live. 

 When in the brood chamber they ex- 

 crete a brown bead-like frass, the food 

 for this sex evidently being cut loose 

 and passed back by the female. The 

 female commences feeding as soon as 

 she has cut into the edge of the bark, 

 and feeds until she is too feeble to form 

 egg cells. 



The burrows of PJilosotinhtis Ihninaris 

 can be very easily distinguished from 

 those of Seolytus ruf/ulosus, both from 

 the outside and on the inside of the 

 bark. The opening of the burrow of 

 the former is ver}^ easily distinguished 

 from the fact that the exudation from 

 the burrow is held together by a fine, apparently silklike thread, 

 which is secreted by both male and female. This holds the exudation 

 over and partly in the mouth of the burrow. After going into the 

 sapwood the female constructs a niche which later forms an arm 



Fig. 18. — Work of the peach-tree 

 barkbeetle {PJilwotribus Umi- 

 jwris) : Galleries in limb of 

 peach tree, November 20, 1908. 

 (Original.) 



