474 INSECTA. 



contracted, and the last part of it is enlarged into a bag, forming most 

 probably a fluid, which is the whole excrementitious part of the animal 

 while in the chrysalis state. 



The ducts entering the gut become larger, and form themselves into 

 kinds of bags near their opening into the gut, and have in them near to 

 their openings some yellowish mucus, similar to that which we find in 

 the gut and bag at the anus. The bag at the anus is generally pretty 

 full of a yellowish mucus, mixed with some that is a little reddish. 

 This mucus at first is the remains of the contents of the stomach and 

 guts, which is in part thrown out in the intermediate state between the 

 maggot and the period of spinning ; in the intermediate state between 

 the chrysalis and moth, they throw out more of it ; also while they are 

 in the moth-state ; but most so when they are in the infant moth-state, 

 viz. when copulating. 



As they do not eat after the caterpillar-state, it appears strange 

 how the gut can have a mucus in it, and even accumulate it, so that 

 the bag at the anus should become a reservoir for the mucus. 



The only way in which I can account for this at present, is to sup- 

 pose that there is a retrograde motion given to the juices of the body ; 

 that the vessels which open at the beginning of the gut, which I shall 

 suppose carried the chyle from the gut over all parts of the body for 

 nourishment, are now employed in bringing back those very juices in 

 the form of excrement. 



The lateral tubes which ramify on the great gut, the canal for the 

 silk, the skin, &c, which were black in the caterpillar-state, lose their 

 attachment as these parts decay, and become larger and larger, more 

 loose, and filled more and more with air, losing the dark colour and 

 becoming white ; and at last many of them appear to become floating 

 air-tubes, loose in the cavity of the belly, so that the moth has a vast 

 quantity of air in the belly. 



Of the female. — The female is larger in the belly than the male ; but 

 I believe this is owing to the vast number of eggs in that cavity 1 . 



The external parts, which include the anus, project very much beyond 

 the body of the animal (more especially before she has had the male), 

 and form a rounded termination on each side of the opening, making a 

 vertical slit between, on which there are a great many small hairs. 

 Under the anus is a thin horny scale of some length from side to side, 

 concave on the upper surface, as it were, half surrounding the lower 

 surface of the anus. 



The internal parts of generation consist, first, of eight oviducts, four 



1 [Hunt. Preps. Phys. Series, Nos. 2601, 2602, 3033—3035.] 



