450 BRITISH BUTTERFLIES. 



pupation takes place in the Berlin district from the middle of June 

 onwards. 



Newly-formed pupa (rutilus). — When first the larval skin is 

 thrown off, the pupa is very pale in colour. The darkest part is the 

 dorsal vessel, which, in the pupa. I watched, beat regularly 60 times a 

 minute. This action can Only be observed for a very short time after 

 the larval skin has been cast. Head not visible from this point of 

 view. Prothorax pale translucent greenish-grey, the marks of the 

 spiracles visible as elongated ochreous spots (dorsal vessel not visible 

 on prothorax) . Meso- and metathorax and wing-cases of the same colour 

 as prothorax; the dorsal vessel dark grey-green. The abdomen pale yellow 

 in the dorsal and subdorsal areas, with brownish blotches on the 3rd, 

 4th, and 5th abdominal segments in the subdorsal area. On the lower 

 border of this area there are dark spots on the 3rd, 4th, and 5th 

 abdominal segments, and below these are pale circular spots on the 

 2nd, 3rd, 4th, 5th, and 6th abdominal segments. Some way lower 

 down are the narrow white spiracles. The spiracular area is greenish- 

 grey, dotted with white, and is bordered dorsally by a serrated line. 

 The 8th and 9th abdominal segments are invaded by the dorsal yellow 

 colour, the dark dorsal vessel being here scarcely discernible. After 

 about an hour, a faint line appears down the centre, and moss-like 

 marblings come on the subdorsal region of the prothorax. The 

 inner and outer margins of the wing-cases become darker green. A 

 second pale spot appears below, and partly behind the pale spots 

 already mentioned as occurring on the abdominal segments. Beneath, 

 the pupa is greenish-grey, but the prothorax and the segments beyond 

 the wings are ochreous-grey. In three to four hours after the larval 

 skin is cast the ground colour of the pupa has changed from green to 

 brown, and all the darker markings have become still darker (Sich). 



Pupa [From pupal-shells of British C. dispar] . — These strike one as 

 being very large, notwithstanding the considerable size of the butterfly. 

 The pupae of all the Lycasnids seem rather large in relation to the size 

 of the body of the imago, but the large relative spread of the wings no 

 doubt requires a supply of fluid for their expansion, normal in pro- 

 portion to the wings, but large in proportion to the size of the body of 

 the insect. The pupa is 16'Omm. long, 6 - 5mm. broad, and 6'Omm. 

 high at the 8th abdominal segment, where it is most robust. At the 1st 

 abdominal segment it is only about 5'Omm. wide or high, but dehiscence 

 makes accuracy here only comparative, and forwards impossible; but the 

 abdomen is certainly more full, more nearly spherical, than in the pupa 

 of B. phlaeas ; the total length of the abdomen (parallel to venter) is 

 8-0mm. (obliquely from front of 1st abdominal to cremaster, 9-Omm.). 

 The girth varies very much; in one it is a fairly compact strand, but 

 obviously of several threads lying between the 1st and 2nd abdominal 

 segments. In others the separate threads are more or less scattered any- 

 Avhere between the mesothorax and 3rd abdominal segment. The colour 

 of the shells differs much from that of those of R. phlaeas; it is a warm 

 ochreous and brown, whilst in B. jtldacas it is a yellowish-grey and black. 

 There is nowhere any black, simply the two tones of pale ochreous and pale 

 brown, differing a little in intensity in different specimens ; only on 

 the prothorax is the tone a little paler (or whiter). On all is a series 

 of oblique pale bands (oblique downwards, or ventrad, and backwards) 

 on the abdominal segments, but lost on the hinder ones, each band 



