392 MR. E. B. POULTON ON THE COLOUR-RELATION BETWEEN EXPOSED 
in the two rows may have pupated soon after 11 p.m., September 5, and thus may 
have only spent two-thirds of Stage III. on the frame. I do not urge this because of 
the confliction of the results with A and C, but because of the earlier transference 
experiments, in which results were distinctly shown to follow from exposure during 
the whole of Stage III., and this in spite of the previous influence of colours tending 
to cause an opposite effect (see results of Series IX., B.). It now remains to add 
together the most trustworthy results of this experiment as shown in the last Table, 
and the most trustworthy results of the similar experiment in the last series (XII., D.). 
Degrees of colour. 
0) 
(2) 
Very 
dark 
(3) 
Dark 
(3) 
(3) 
Light 
(3) 
Very 
light 
(3) 
(4) 
(5) 
A. Larger skin area in black, 
smaller in gilt for 
Stage III. 
1 
1 
1 
• • 
• • 
= 3 
B. Entirely exposed to gilt 
for Stage III. 
1 
• • 
* * 
5 
1 
— < 
C. Largest skin area in gilt, 
smaller in black for 
Stage III. 
* * 
• ‘ 
* * 
* * 
1 
2 
1 
• * 
1 
= 5 
D. Entirely exposed to black 
for Stage III. 
5 
2 
1 
II 
w OO 
The comparison between A and C, and between either of them and B, entirely supports 
the above-mentioned conclusion, while such results cannot be made to harmonise with 
the theory of a sense organ of this kind in the head. The results of D remain as a 
difficulty under any theory, and I can only account for it by supposing that the 
individuals were unusually light. 
At the close of these long series of conflicting colour experiments, entirely directed 
towards the settlement of the important question of the position of the sensory surface, 
I must again point out that all the results which were to be gauged have been 
acquired from the influences working during Stage III. only, and very often for only 
part of it, and that all previous experiments of the kind have pointed towards the 
conclusion that such results must be highly irregular, and can only be brought to bear 
as evidence by the use of large numbers. I could not, and did not, expect that the 
results would be more regular than they have proved to be, but I expected sufficiently 
clear results to confirm or to upset the conclusions arrived at from the numerous 
blinding experiments, and I think that the results have ended in as complete a 
confirmation as the necessarily limited conditions of experiment could be anticipated 
to produce. It will be unnecessary to further summarise any of the conflicting colour- 
experiments. 
I). Finally, towards the close of the experiments, 20 pupae were found on the food- 
