132 THE FOREST TENT CATERPILLAR 



much tramped upon by people or animals, scatter over this 

 the cocoons as they are collected, not making the layer more 

 than an inch deep; leave the cocoons in this position until 



• 



the moths begin to emerge ; then rake the cocoons up and 

 burn them. During the week or ten days that the cocoons 

 remain here most of the parasites will have left them and 

 found shelter in the turf, where they will complete their devel- 

 opment. By keeping two or three hundred cocoons in a box 

 under observation, the time when the first moths come out can 

 be readily determined. 



