172 CABBAGE. LEAVES — CABBAGE MOTH. 



which, as we shall presently see, it is nearly related. When it is 

 disturbed, with a wriggling motion it runs briskly backwards, or 

 by a fine cob-web like thread lets itself down from the leaf. Its 

 castings are little black grains, which appear like gunpowder 

 sprinkled thickly over the leaves and the ground beneath them. 

 The pupa or chrysalis is enveloped in a very pretty gauze-like 

 cocoon, which may be found attached to the eaten 

 leaves, two or more of them frequently in a clus- 

 ter together. It is spun of clean white threads, 

 crossing each other and forming an open net work, through the 

 meshes of which the enclosed chrysalis may be distinctly seen. 

 The threads composing the net-work are coarsish' and not very 

 stout. They may readily be broken with the point of a needle, 

 and the inclosed pupa be thus removed from its case for exami- 

 nation, though the cocoon is so slightly attached to the leaf that 

 it is frequently torn loose in thus breaking it open. 



Interspersed with these gauze-like cocoons upon the leaves, 

 others maybe met with quite different in their appearance, being 

 opake and of a thick paper-like texture and a brown color. They 

 are of an eliptic form, rounded at both ends, and only about the 

 tenth of an inch long and a third as broad. These have been 

 constructed by the larvse of parasitic Ichneumon-flies which have 

 destroyed the worms of the cabbage moth. And from the infor- 

 mation I possess, it appears that this parasite deposits but a single 

 egg in each worm, from which a maggot hatches, which feeds 

 internally upon the worm, yet without attacking any vital part 

 whereby the worm would be prematurely destroyed. Thus the 

 parasite, as in other cases of this kind, attains its growth at the 

 same time that the worm reaches maturity, when the maggot 

 finishes its work by destroying the little that remains of its foster 

 parent, and immediately incloses itself in this paper-like cocoon. 

 Of three mature worms which I enclosed in a small box over 

 night, only two were found the next morning. All vestiges of 

 the third had disappeared, and in place of it was one of these 

 paper-like cocoons. 



But as the worm of the Cabbage moth is such a choleric, mer- 

 curial little fellow that when he is molested, be it ever so slightly, 



