Adjustment of colour in various 'pupas, etc. 398 



are practically hone-coloured (3 a). The green pupae are 

 equally deficient in pigment and may be regarded as a 

 dimorphic form of this degree (8 h). These relationships 

 may be conveniently expressed as follows : — 



1. Dark. 



2. Intermediate. 



8. Light. (a) Bone-coloured, 

 (h) Green. 



(1) The Dark pupa?. The ground is bone-coloured. 

 Black pigment is strongly developed on each side of the 

 dorsal sui'face, forming a large sub-rectangular patch on 

 each side of each abdominal segment, fusing into an 

 irregular mass anteriorly, on each side of the thoracic 

 region. The dorsal line is marked posteriorly by a distinct 

 dot on each segment. Seven dots can be recognized, 

 including one on the caudal spine. There is also a large 

 pigment patch on each side of the mesothoracic keel and 

 on each side of the anterior rostrum. Minute black points 

 are scattered between the sub-dorsal pigment and that of 

 the dorsal line. 



On the sides, the principal development of pigment is on 

 the wings, in which part of the venation is thus rendered 

 conspicuous, while the outline of the hind margin of the 

 futui'e wing is marked by a distinct row of black dots. 

 Near the centre of the wing is the " wing-mark " made 

 up of two or more, generally three, intensely black patches 

 — the largest inferior — apparently occupying spaces 

 between the veins. Even in the darkest forms these 

 patches are nearly always conspicuous from their superior 

 blackness : they often tend to fuse, forming in many cases 

 a single large patch. 



The eye is strongly pigmented superiorly, biit below and 

 including the crescentic mark upon which alone of the 

 entire pupal surface the facetted structure is developed 

 (the pupal eye), it is devoid of pigment. 



(2) The Intermediate pupae. The ground is bone- 

 coloured. These pupae differ from the last, with which 

 they are connected by transitional forms, in the lesser 

 development of black pigment both dorsally and on the 

 wings. As a rule the diminution is proportional throughout, 

 but in certain cases the dorsal pigment may retain its 

 full development. 



The lesser amount of black pigment renders the intense 



