GYPSY AND BROWN-TAIL MOTHS. 17 



How they work in effecting the control of the moth in their 

 native country is hest indicated in the table, which, while it 

 needs explanation, tells the story much plainer than it would be 

 possible to tell in words. Opposite the name of each parasite, 

 extending across a certain number of the vertical columns, is a 

 dotted and a solid line. The vertical columns indicate different 

 stages in the development and transformations of the gypsy 

 moth, as egg, caterpillar and pupa, and these are still further 

 divided into caterpillars of different sizes and eggs and pupse 

 of different ages and conditions. At the head of each column is 

 stated the approximate number of days during which the indi- 

 vidual gypsy moth remains in that particular stage. 



The dotted line following the name of the parasite indicates 

 those stages in the life of the gypsy moth during which it is 

 liable to be attacked by the parasite in question, and it will be 

 seen that in a number of instances, as, for example, Chalcis and 

 Theronia, this period is exceedingly short. The solid line indi- 

 cates the stages in the life of the gypsy moth during which it is 

 likely to contain the parasite in its body. This, it may also be 

 noted, varies considerably. Orossocosmia, for example, gains 

 lodgment in the active caterpillar while it is only about half 

 grovm, and the extension of the solid line across all of the 

 columns which stand for the later caterpillar stages, as well as 

 for all of the pupal stages, indicates that the larvae of this para- 

 site do not leave the host caterpillar until after it has trans- 

 formed to a pupa, and until the moth wDuld naturally have 

 emerged had the pupa remained healthy and unparasitized. 



The main fact, which it is particularly desired to emphasize, 

 is that every stage in the transformations of the gypsy moth, 

 from the time the eggs are first deposited until the caterpillars 

 are full grown and transformed to pupae, is subject to the attack 

 of one or more parasites. It is also liable to attack at any time 

 throughout this period except during the cold weather in the 

 winter, when there is no insect activity. This is exactly what 

 is meant by the sequence of parasites, and, in the opinion of 

 those most thoroughly informed, it is the condition which it is 

 absolutely necessary to bring about in America before complete 

 control can be eifected. 



