144 Dr. T. A. Chapman's notes on PiipcT, 



Pterophori whose formula is the same. More important 

 as showing a separation is the fact that it preserves the 

 habit of emerging from its cocoon before the exclusion 

 of the moth; Pteropliorns being fixed by a cremasfcer 

 and usually making no cocoon. The great development 

 of the dorsal head-piece is another very distinctive 

 character ; the dehiscence also is very different. 



The cocoon of the American Penthetria parvula is 

 extremely similar, but more regular and elaborate. Its 

 pupa retains a very simple tineoid character, so that 

 there is no doubt a considerable gap between these two 

 forms, but there can be little doubt that the cocoon 

 structure has a common ancestry and is not an inde- 

 pendent invention. 



Pterophoros. — The ovum is of oval section in every 

 direction, a form that may most easily be described as 

 that of an ordinary bird's egg, if laid on its side and 

 then flattened. The different species I have examined 

 vary in their size and in the proportion of their different 

 diameters, but all have this general form : they are 

 smooth, bright, and polished, and have faint mai'kings 

 of a network tending to a hexagonal mesh. 



In some cases the narrowing towards the small end 

 is not so evident, and in others {hipunctidacfylns) the 

 egg might almost be called cylindrical, so that there is 

 considerable variation within definite limits which may, 

 of course, be exceeded in species whose eggs I have not 

 seen, but I have seen no suggestion of such a form as 

 occurs in Chnjsocorys. 



The larva of most of our Pterophori are well known, 

 and I don't know of one whose characters are at all like 

 those of Ghrysocorys — either as to the retention in all 

 stages of the same arrangement of hairs and tubercles, 

 or in having at any stage precisely the same arrange- 

 -ment as in Ghrysocorys. 



The pupa of Pterophorus is highly specialised, yet 

 retains several of the most definite characters of the 

 Incomplete. Only the three first abdominal segments 

 are fixed, the next three (and four in (? ) are free, the 

 antennae and maxillfe adhere to the head-piece and 

 separate from the other parts on dehiscence, the eye- 

 covers going with the dorsal head-piece. It possesses 

 a very special and elaborate set of terminal hooks, by 

 which it fixes itself to a pad of silk, these are supple- 



