LEPIDOPTEROUS PUP2E AND THEIR SURROUNDING SURFACES. 
321 
together with the resulting pupal colours, which are given in numbers corresponding 
to the standard list described above. The comparison was made August 19, 1886. 
A. A number of larvae were placed in a transparent glass cylinder on a white 
plate, which, however, soon became dark from the larval faeces. The food-plant 
passed through a hole in the plate into water beneath, and the top of the cylinder 
was covered with white muslin, much darkened and discoloured by age. Upon this 
disc of muslin, only 9 centims. in diameter, 18 pupae were crowded, not one occurring 
in any other part. These were coloured as follows :— 
pup* were (1). 
( 2 ). 
„ (3), 2 of these approaching (2). 
,, dead and discoloured. 
18 
It will be seen by a comparison with other experiments that the especial darkness of 
this lot of pupae was due to the mutual influence of the dark bodies of the larvae 
themselves hanging close together upon a limited space. 
4 
6 
6 
2 
B. Another lot of larvae were placed in a larger cylinder, but with arrangements 
similar in other respects. Eight pupae were suspended from the muslin top, 1T0 deci¬ 
metres in diameter, while five others were suspended from the food-plant. They were 
coloured as follows :— 
Of the 5 pupae on the food-plant 1 
Of the 8 
muslin 
2 
2 
1 
1 
5 
was (2). 
were (3). 
were dead and discoloured. 
had produced an imago, but the pupa was probably (3) ; 
certainly this or (2). 
was (2). 
was (4), with the gold of (5), 
were dead and discoloured. 
13 
This set compares in an interesting way with the last; being far less crowded on 
the larger area of muslin, there was a much smaller proportion of dark environment 
to each larva, and the whitish muslin could also produce its effect. Hence a much 
lighter series of pupae are obtained, with more gold upon them. Comparisons of this 
kind led me to continue the investigations upon this species with much greater 
minuteness, as will be seen below. 
C. Another lot of larvae were placed in a cylinder surrounded by a single layer 
of green tissue-paper, which had become very yellowish-green from the action of light. 
MDCCCLXXXVII.—B. 2 T 
