254 BRITISH LEPIDOPTERA. 



tough, brown silk (in texture it reminds one ot a cane-chair bottom 

 on a miniature scale, only the mesh is relatively coarser), exceedingly 

 stiff, hard and very strong, the individual silk threads being thick and 

 stout, and having the appearance of coarse isinglass. The rupture 

 in the ? cocoon is not exactly at the top, but slightly to one side 

 or to the shoulder ; in one specimen the pupa forced its way entirely 

 from the cocoon, in the other only partly, viz., as far as end of 

 4th abdominal. The cocoon appears to be ruptured by the threads 

 being frayed or worn through, and Bacot considers this is done by the 

 serrate-edged V sria P e d ridge on the anterior beak-like face-piece of 

 the pupa, between the bases of antennae, and he suggests that probably 

 the pupa revolves and forces its head against the shoulder of cocoon. 



Pupa. — The pupa is of a dingy blackish-brown colour, exceed- 

 ingly rugose, and thickly covered over with minute blackish points. 

 The skin is remarkable for its dense solidity. The head is 

 ventral, the antennae (which are very curved) originating on 

 the front of the prothorax and extending ventrally as a ventral 

 margin to the edge of the wings. A small prominence at the base 

 of the maxillae. The legs well-developed, the antennae strongly 

 segmented. The wings very narrow, compared with the size of 

 the imaginal structures, the costal margins meeting much before 

 the apex. The glazed eye indistinct and sunk in a depression 

 near base of antenna. There is a remarkable beak or cocoon- 

 opener, very like that of a Cossid or Sesiid. This beak is 

 placed between the antennae, and has a strengthening ridge 

 running back on each side ; above the labrum is a blunt pro- 

 jection of some prominence, and on each side the lappets, that are 

 jaws, or the jaw -covers of the face; maxillae large in centre. 

 A portion of the head (between ridges of the cocoon - opener) 

 is directed forwards, but is part of the face-piece ; there is no 

 dorsal headpiece. The prothorax prominent with three short 

 longitudinal ridges on its front face. The prothoracic spiracle 

 deeply placed and conspicuous. The mesothorax well-developed, 

 the metathorax narrow. The ist, 2nd and 3rd abdominal segments, 

 although narrow from front to back, are much fuller than the 

 thoracic segments. The 4th, 5th, 6th and 7th abdominal segments are 

 much larger, and movable incisions occur between the 4th — 5th, 5th — 

 6th and 6th — 7th, and the movement between 7th — 8th appears to have 

 been only recently lost. The intersegmental membrane* is smooth and 

 black, very different from the rest of the pupal surface. The dorsum of 

 the 5th, 6th and 7th segments, and to a less extent the 8th, is thickly 

 studded with projecting sharp points, chiefly collected in transverse 

 rings on the front and back of each segment, but not entirely so. 

 They are less strongly marked ventrally, but still there is one well- 



* An important feature of the pupa is the existence of a structure called in 

 butterfly pupae, where it is more obvious than in other pupae, the intersegmental 

 subsegment, and -which is rarely to be detected with any certainty in Heterocerous 

 pupse. It is obscurely indicated in some Citheroniids, but in D. versicolora it is 

 very obvious as a dividing line near the posterior margin of the abdominal segments 

 4, 5 and 6, between the scars of prolegs and the spiracles, and can be followed 

 round the segments ; on the 7th abdominal, the obvious portion that looks like 

 ankylosed intersegmental membrane is more probably really this structure, and not 

 the remains of true intersegmental membrane, which possibly do not here come to 

 the surface (Chapman). 



