256 Experiments upon the colowr-relation, de. 
5. ExPERIMENTS WITH VARIOUS CoLouRS :— 
I. Black. 
A. In these experiments the paper used was opaque, 
and, in addition to the complete lining of the jars with 
the black paper, the square pieces of glass surmounting 
them were previously densely smoked on the side placed 
uppermost. 
Data.—Hight larve, all of which pupated Sept. 3rd 
to 15th. In one case the lamp-black was accidentally 
rubbed off from a small area (by a finger-touch), and the 
contained larva selected this particular spot for pupa-. 
tion. This case does not therefore properly belong to 
this series, but it is interesting to retain it for the sake 
of comparison. 
Results.— 
2 pupe were dark (1), 1 typical and pinkish, while the other had 
been accidentally injured. 
PAVERS & (1), 1 typical and yellowish, while the other had 
also been injured. 
Beer ‘3 (2), 1 distinctly pinkish, the others faintly so. 
Te is », light (8), being the pupa upon the clear area on the 
_ blackened glass. 
8 
B. An additional pupa, which was found on ‘tarred 
stones on the top of a wall at Clevedon (Somerset), on 
October 3rd, must also be included here. When finally 
examined it was dead, but from its appearance it could 
safely be classed as a (1) yellowish, and Mr. Griffiths’ 
description of it when alive is as follows :—‘‘ Very dark 
grey; spots profuse, black angles and wing-cases; 
median line greyish, much interrupted by spots.” This 
occurrence is an interesting one, as it affords an instance, 
as Mr. Griffiths remarked, of a larva voluntarily selecting 
the black surface to pupate upon, after crawling over 
the lighter-coloured untarred stones of the wall. 
These results confirm those obtained by Mr. Poulton by 
the use of black surroundings, except that there is here no 
evidence of the illumination producing any effect. There 
was also another point in Mr. Poulton’s paper which 
was confirmed by these results. Mr. Poulton had found 
that darkness had the effect of prolonging the period 
before pupation, and remarks, in his paper, that* 
* Page 482. 
