Adjustmeiit of colour in various pupse, etc. 375 



A light yellow-green form (1 a) is bright yellow over the 

 dorsal surface slightly mottled with green on the sides, this 

 colour becoming distinct round the spiracles and forming 

 a spiracular streak interrupted between the abdominal 

 segments. At the posterior extremity of the pupa this 

 green streak is continued on to the sides of the anal spine, 

 and in the more strongly marked pupas of this degree the 

 wliole of the spine is green. The green mottlings are 

 rather more distinct upon the abdominal segments below 

 the spiracular band than they are above it, and have a 

 more pronounced longitudinal arrangement. The dorsal 

 region of the thorax is also more or less mottled with green 

 which becomes concentrated to form a distinct apical patch 

 on the mesothoracic median spine. The wings, limbs, 

 antennae, and head are deep green, the latter being, in the 

 palest pupae, the most strongly coloured part of the whole 

 surface. 



In the more deeply coloured of the light forms (1 a) 

 the mottled green tends to spread backwards from the 

 mesothoracic spine forming a broad indistinct greenish 

 band. 



In the darlc, ydlow-grccn pupse (1 li), further development 

 and coalescence of the mottlings transform this dorsal band 

 into deep green. It occupies the whole dorsal area between 

 the subdorsal rows of small tubercles. Below, the green 

 of the spiracular stripe, — continuous in pupas of this degree 

 — spreads upwards and invades the yellow ground-colour 

 leaving only a yellow lateral band, sharply defined above 

 where it terminates at the level of the subdorsal tubercles, 

 while below it gradually passes into the invading green. 

 Anteriorly this yellow band terminates below the meso- 

 thoracic spine. The dorsal green band is palest (yellowest) 

 in its median part and in the posterior half of its length, 

 in front of the caudal spine, the dorsal surface of which is 

 green. The band is also interrupted in the region of the 

 metathorax by a yellow patch, traversed by a green median 

 line. 



The light grey forms (2 d) resemble the light yellow- 

 green (1 a), substituting bone-colour for yellow, and dark 

 purplish-brown for green, allowing of covirse for the greater 

 contrast between ground-colour and marking which is thus 

 brought about, and for the difference over the wings which 

 has been already alluded to. 



The dark grey forms (2 6), by making a similar substitu- 



