LEPIDOPTEROUS PUPH3 AND THEIR SURROUNDING SURFACES. 
413 
These pupae are decidedly darker than those of the preceding subdivision, and yet 
they were freely exposed to light: on the other hand, they are less dark than the 
wild larvae found on the tarred fences, which, although shaded (in my own obser¬ 
vations), were probably in a stronger light than that to which the pupae of this 
subdivision were exposed. These results seem to show that, at any rate in P. rapes, 
the stronger illumination of a black surface tends towards the production of stronger 
effects, just as would be the case with a white or green surface, while the direct 
white light falling on the larval surface produces no antagonistic effects. 
C. 
September 15. Four pupae were found at this date upon a black tarred fence in a 
shaded lane at Seaview, and they were compared with the other pupae examined 
on this date. All were (1), very dark ; two pinkish, and two so dark that the ground- 
colour could hardly be made out, but probably yellowish. These results are very 
uniform, and show the influence to have been very strong. It has already been 
mentioned that the pupae were in most cases concealed in angles and corners, &c., 
and this was also true of the succeeding pupae. 
D. 
October 5.—Three pupae of P. rapes were found October 5 on a black tarred fence 
in a shaded lane at Seaview. All were (1); one very black, one normal, and one 
rather light for this degree and distinctly pinkish : the others being very dark grey, so 
that the ground-colour was almost entirely concealed, hut apparently pinkish in one 
pupa and yellowish-pink in the other. These results are very uniform and highly 
protective. 
E. 
Mr. W. H. Harwood kindly sent me 11 pupae of P. rapes fouud upon tarred 
palings, and all of these were (l); five extremely black, two normal, and one very 
grey rather than black; three dead, but apparently very dark as far as could be 
ascertained from the large amount of pigment on the pupal wings. The ground¬ 
colour seemed to be pinkish in all cases. These results are exceedingly uniform, and 
show the very strong effect of the black surface. 
In concluding the effects of black, it will be of interest to give a tabular analysis of 
the effects of this background, in various degrees of illumination, upon P. rapes :— 
Degrees of colour. 
Dark (1) 
(1) 
(2) 
(3) 
(4) 
(5) 
I., A. Black background in darkness . 
3 
1 
„ B. „ „ somewhat shaded . 
4 
i 
5 
• . 
• . 
” | ,, „ less shaded . . j 
4 
I 
o 
Li 
• • 
• * 
* * 
,, E. ,, ,, probably less shaded 
.5 
6 
