476 INSECT PESTS OF FARM, GARDEN AND ORCHARD 



Life History. The beetles emerge from the trees in April and 

 May in the Middle States. The female burrows through the 

 bark, and partly in it and partly in the sap-wood she eats out a 

 vertical gallery or brood chamber, along the sides of which at 

 short intervals she gnaws out little pockets in which she places 

 her eggs. The larvae hatching from these eggs excavate little 

 side galleries, which branch out and widen as the larvae increase 





m 11 



/ 



FIG. 399. One of the most important native enemies of the San Jose scale, 

 a little black ladybird-beetle (Microweisea misella): a, beetle; b, larva; 

 c, pupa; d, beetles, larvae, and pupae, among scales all greatly enlarged. 

 (After Marlatt, U. S. Dept. Agr.) 



in size (Fig. 401). The larvae become mature in about three 

 weeks, when they form cells at the ends of their burrows and 

 transform to pupae, from which the adult beetles emerge about a 

 week later. There are probably three generations a year in the 

 Middle States according to Dr. Chittenden. 



Were it not for the effective work of parasitic and predaceous 

 insects which prey upon it, this insect would be a most serious 

 pest. One of the most valuable of these is a little chalcis-fly * 

 of which Dr. Chittenden bred 92 specimens from 72 of the develop- 



* Chiropachis colon Linn. 



