ON THE LARVA OF LIPHYRA BRASSOLIS. 255 



but the labial palpi are very evident beneath them. The most 

 special feature of the pupa is a set of flanges, or raised ribs. If 

 the pupa were divided into a dorsal and ventral piece, by a 

 section through its widest dimensions, the line of section would 

 mark one of these ribs, which starts round the abdominal seg- 

 ments from the anal angle of the wings (end of vein Ic), and 

 goes round the end of the pupa, dividing the last segment into 

 two portions; this segment is consequently of considerable antero- 

 posterior dimensions, stretching a good way under the pupa, but 

 also having a portion, as it were, lifted right out on to the dorsum 

 by having to be above the flange. The segmental incisions are 

 all raised into double ridges, but ventrally, i. e. below the mar- 

 ginal flange above noted, but with no trace of anything of the 

 sort above it, each segment has another single ridge or flange 

 about one-third of the way in front of each incision. The scars 

 of prolegs are well-marked by large areas into which these ribs 

 do not intrude. 



These flanges are obviously the remains of the great marginal 

 border of the caterpillar, and of the division beneath it of each 

 segment into two. The marginal ridge extends forwards through 

 the wings, but the pupal shell is so delicate that it is diflicult to 

 say whether this ridge is in the wing- covers, or an indication of 

 a flange on the segments beneath them, showing through. 



The spiracles are more obvious than in the larva, and occupy 

 a similarly dorsal position. The pupa is very smooth and 

 polished at least thoracically ; the abdomen has very numerous, 

 almost microscopic hair-points. 



I have also a specimen of the pupa within the larva skin. 

 This fully illustrates Mr. Dodd's account of how pupation 

 occurs. The larva skin becomes a little altered by the dorsum 

 being rather raised and rounded, but substantially it is the 

 adult larva one sees, and this forms a case or cocoon, precisely 

 as happens in the pupation of the Muscidae. 



The pupa inside lies quite free from any attachment to the 

 skin, but the ventral depression of the pupa is due to its having 

 to fit on the ventral aspect of the larval skin, which is raised 

 centrally by the head, legs, prolegs, &c. 



The larval skin dehisces by cracking round the marginal 

 crest in front, by a crack across the front of the three ridges, 

 i. e. between third and fourth abdominal segments. The semi- 

 circular portion thus marked off again divides longitudinally 

 into two portions ; in my specimen one of these portions is 

 missing, the other loose. 



[A plate illustrating the early stages of Liphyra brassolis is 

 being prepared, and will be published in the present volume. — 



Ed.] 



