Experiments upon the colour-relation, ce. 255 
(3). Still lighter, but with sufficient of the grey 
dusting to obscure the tint of the ground colour and to 
produce a grey or light grey appearance. The black 
patches still occur in the same positions, but they are 
smaller; the same ground colours were recognisable. 
(4). Very light, with little or almost none of the grey 
dusting, so that the ground colour is predominant in 
producing the general appearance. The black spots and 
patches are very slightly developed and sometimes 
entirely absent, except for a few black points on the 
side of the rostrum, which is the last position in which 
traces of the pigment patches are retained. It is, 
however, common to find a slight, but distinct, speckling 
due to minute black points, but not sufficiently numerous 
to combine with the lighter ground tint and produce a 
grey result. The ground colours are much more 
distinct, as they are not dimmed, and are generally 
pinkish, yellowish, or faint greenish, or some combina- 
tion of these. The latter colour is transitional into the 
brighter tints of the next degree. 
(5). In certain pupe the green ground colour is suffi- 
ciently distinct to warrant their classification as a 
separate degree. All varieties of colour are met with, 
from the faint, scarcely perceptible, yellowish green 
tinge of certain pup in the last degree to the more 
distinct and bright yellow greens arranged under this 
head, and finally up to a magnificent transparent 
emerald-green, which forms the culmination of the 
development of this tint as a ground colour. ‘There are 
also dull greens, and sometimes these pupe are dusted 
with grey spots and have the black markings developed 
to a considerable extent (such a pupa is figured plate 26, 
fig. 31, natural size), but, as a rule, these pupe are the 
lightest of all in both these respects. The lens, how- 
ever, shows the existence of minute dots in all cases, 
although in the more extreme forms very few minute 
points can be detected by the naked eye, and there is no 
trace of the black markings even upon the rostrum. It 
is very common in the extreme forms of this degree, and 
in the lightest of the last degree, for the median and 
lateral ridges and the extremities of the body to be of a 
distinct pink tinge.” 
7 2 
