REMARKS ON THE BAG-WORM. 



81 



little conical silken coats, to the outside of which they attach bits 

 of leaves and twigs. These bags are at first held upright (Fig. 

 i,^), but, with increase in size, they are allowed to hang (Fig. 

 I,/). In the autumn, after attaining full growth, the worms appear 

 as in Fig. i, a. They now fasten the bags to the permanent parts 

 of the tree, and transform to the pupa state. In due time, the male 

 pupa (Fig. I, /') pushes down toward the anal orifice, and a little, 

 black, glassy-winged moth (Fig. i, </), with strongly pectinate an- 

 tennae, escapes. 



The female (Fig. i, c) only partly issues from her pupa shell, 

 receives the male, and retreats into the puparium, in which she 

 deposits her eggs. 



Fig. 2. Thyridopteryx EPHEMERi^FORMis : a, folHcle cut open to show the 

 manner in which the female works from her puparium and reaches the end of the 

 bag, natural size; b, female extracted from her case, enlarged. 



In reference to the act of coition, which has not been fully 

 understood by entomologists, I quote from a former article of 

 mine : * 



"We have seen that, by means of the partial elongation of her 

 puparium and her partial extraction therefrom, the female is able 



* Sci. Am., Suppl., April 3d, 1878. 



