LEPIDOPTEROUS PUPN3 AND THEIR SURROUNDING SURFACES. 
335 
demonstration of a somewhat different tendency in the larvae of this company, as a 
whole, from those in the preceding company is of importance. 
Y.—The remnant of a company was found (August 22) on a very large nettle-bed 
close to South Hincksey. From the extent over which the larvae ranged, and the 
amount of nettle which had been eaten, it was evident that the company had been 
very large. Professor Burdon Sanderson was with me at the time, and I spoke of the 
negative results of the blinding experiments, and asked his opinion as to the possible 
presence of the desired terminal organ in connection with the large and complex 
bristles which are present on the larvae. As a result of our conversation, I determined 
to devote the greater part of these larvae to the investigation of this question. I also 
wished, by the careful study of a few larvae of this company, to ascertain as accurately 
as possible the duration of the period between the cessation of feeding and pupation, 
and of its constituent stages, especially II. and III. It was to be expected that 
Stage I. would be abnormally short, as the larvae were confined in so limited a space. 
The stock of larvae were placed at 10.30 P.M., August 22, in the two cylinders 
mentioned in III., A., and IIP, B.; similarly arranged, with “ opal ” roofs and white- 
paper floors, but placed so as to receive a strong east light just beneath a large window. 
The experiments are described below under their respective divisions. 
A. On the evening of August 22 a few larvae were selected to form the subjects 
of experiment to test the above-mentioned suggestion as to whether the large 
branching spines contained any terminal organ which received impressions from 
coloured surfaces, and was thus the means of modifying the pupal colours. There are 
seven of these spines on most of the segments, and when they were snipped off the 
bases bled a little, and so it was clear that a subcuticular core was contained within 
them. 
(a) Four larvae, apparently still feeding, were selected, and their bristles were care¬ 
fully snipped off, being cut as near to the base as was consistent with safety. These 
larvae were placed in one of the two compartments of the gilt box already described, 
which faced a strong east light, standing about two feet from a large window. The 
history of the larvae is given below :— 
