562 INSECT PESTS OF FARM, GARDEN AND ORCHARD 



partly grown caterpillars. The caterpillars emerge just as the buds 

 burst in the spring and feed on the expanding foliage. Where 

 abundant they soon strip a tree, for each of the nests harbors 

 400 or 500 little caterpillars. In five or six weeks they have 

 become full PTOWII and spin thin cocoons of white silk among 



FIG. 414. Egg masses of the brown-tail moth natural size; caterpillars 

 hatching from the mass on leaf at left. 



the leaves, in which they transform to dark-brown pupae. About 

 three weeks later the moths emerge. 



Several native parasites and predaceous bugs prey upon the 

 caterpillars, but do not seem to materially reduce their numbers. 

 In Europe there are several parasites which prey on all stages 

 of the insect and which the State of Massachusetts with the 

 cooperation of the U. S. Bureau of Entomology is introducing 



