Acantho2:)S'i/chc opaccUa. 405 



inflated in the sense of being swollen and rotund, but 

 appeared to be so, so far as pressure between the female 

 and her pupal shell allowed. 



The mechanism by which this inflation occurs I have 

 never determined, but it is doubtless a special modification 

 of that possessed by many insects and especially Lepi- 

 doptera, by which the abdomen is inflated at the period uf 

 emergence from the pupa. 



The female of A. opacella in perfect condition is a very 

 different creature from my previous idea of it, or what one 

 can gather from any published descriptions I have seen 

 except the notes by Dr. Max Standfuss. 



As usually seen and described it is a naked white 

 maggot, with some dark shining head and thoracic plates, 

 some almost recognisable mouth parts and rudimentary 

 true legs. Otherwise it is a mere egg bag. Barrett tells 

 us it has "small tufts of erect soft white hairs at the sides 

 of the seventh to ninth segments." The genuine animal 

 has however a much more elaborate clothing than this, 

 the difficulty is to obtain it with this still in situ. 



My first note is as follows, — " a ^ of ojmcclla in gootl 

 condition, I noticed that the wool with which she lines the 

 mouth of the sac and partially disposes amongst the eggs, 

 arises in five or six tufts placed on each side of certain 

 abdominal segments. I meant to make closer observations 

 later, but when I came to do so, she had rubbed the wool 

 off, and I have not again succeeded in finding a $ with 

 the wool perfect, she begins to rub it off in her first 

 journey to open the mouth of the sac, and though keeping 

 a sharp eye for sacs at this stage, I have so far always 

 found the $ ah'eady denuded and the wool loose in the 

 mouth of the sac and of the pupal shell." 



The $ larva increases the length of the funnel at the 

 open end of the sac, which serves to hold the pupa whilst 

 he emerges, and which consists of little else than silk 

 without any covering of chips of bark, wood, etc., but he 

 makes no other addition to the sac. The $, on the other 

 hand, may repair and trim up the mouth of the sac, but 

 practically leaves it of its larval size and structure ; but 

 within this, she closes the mouth of the sac by spinning a 

 quantity of silk as a loose network, so that it forms a sort 

 of cocoon, in front of and in some extent fitting the 

 anterior of the pupa, between it and the mouth of the sac. 

 In opacella this spinning does not extend backward, but in 



