208 



THE STUDY OF INSECTS 



The adults fly very swiftly and during the hotter part of the day. They 

 frequent flowers thus increasing their resemblance to bees or to wasps. 

 The larva' are borers, living within the more solid parts of plants. Some 

 species cause serious injury to cultivated plants. More than one hundred 



Fig. 358. — Wings of Synanlhedon exitiosa. 



Among the better 



species have been found in America north of Mexico. 

 known species are the following. 



The blackberry-crown borer or the raspberry-root borer, Bembecia 

 marginata. — The larva of this species burrows in the roots and lower 

 part of the canes of blackberries and raspberries, sometimes completely 

 girdling the cane at the crown. 



The peach-tree borer, Synanthedon exitiosa. — This is one of the most 

 important enemies of the peach-tree. The eggs are laid on the bark of 

 the tree near the ground. The larvas burrow in the inner bark and sap- 

 wood just below the surface of the ground. Their injuries cause the 

 tree to exude large masses of gum which collect around the base of the 

 trunk. The insect passes the winter as a larva and in the spring makes a 

 long cocoon at the surface of the ground. The moths appear from May 

 to October. 



The steel-blue female moth has (Fig. 359) the 

 fore wings covered with scales, and there is a bright 

 orange-colored band on the abdomen. In the male 

 both pairs of wings are nearly free from scales. 



The Pacific 'peach-tree borer, Synanthedon opa- 

 lescens. — On the Pacific Coast there is a peach-tree 

 borer that is distinct from the above, and appears 

 to be an even more serious pest. The larva is more 

 difficult to remove from the tree, as it bores into the solid wood. The 

 female of this species lacks the orange-colored band on the abdomen. 



TT 



Fig. 359. — Synanthedon 

 exitiosa, female. 



