408 Dr. T. A. Chapman 07i 



holds it ; one appreciates what an admirable protection it 

 must afford against small marauders of all sorts, but 

 wonders a little how the moth herself passed so easily 

 through it to and fro, and yet left the wool so admirably 

 disposed as it is, since her last act is to leave the sac, by 

 passing through this obstacle. 



The female moth does not always drop out of her sac if 

 unfertihsed, but often dies within it. But if all goes well 

 she always does so, as soon as she has laid all her eggs. 

 ]f found immediately, one is surprised to observe that she 

 has diminished in bulk to a very trifling degree. It is 

 easy to see that the bulk is obtained by the inflation of 

 the abdominal cavity with air. The use of this arrange- 

 ment, as in some of the lower Psychids which have a pre- 

 cisely similar habit, one may safely conclude to be to 

 prevent collapse to a state of absolute flaccidity, when 

 muscular action would be impossible owing to the approx- 

 imation of all the parts rendering further movement 

 impossible, yet muscular action is absolutely necessary to 

 complete the egg-laying and the emergence of the effete 

 moth from the sac. The falling out of the moth is pro- 

 bably a provision to admit of the elastic silk structure in 

 the throat of the sac to close, a closure completed by the 

 wool off the moth entangled with it, making it impervious 

 to any enemy unacquainted with its valvular arrangement. 



If the moth died amongst the silk she would not only 

 hold it open but herself form an edible highway to various 

 enemies. 



In special connection with the Psychids, some questions 

 as to homologies of the neuration in various Lepidoptera 

 have forced themselves on my attention, and I was glad to 

 be able to examine some specimens of A. opacclla, to get a 

 little light on the matter. 



There are in Lepidoptera four internal veins in the fore 

 wings of all pupse I have so far examined. Of these the 

 first is not truly an internal vein, but is a branch of the 

 cubitus. It has however been for so long called an in- 

 ternal vein (Ic of Meyrick and Hampson, 1st anal of 

 Comstock) that I fear it must continue to be so named, it 

 is however given off at the base of the cubitus (the main 

 vein giving rise to 2 and 3 of Meyrick and Hampson). 



The three other internal veins arise by a common stem 

 quite separately from the cubitus. The first of these (lb 

 of Meyrick, 2nd anal of Comstock) is the one that is so 



