LEPIDOPTEROUS PUPH1 AND THEIR SURROUNDING SURFACES. 
411 
considerable extent (such a pupa is figured Plate 26, fig. 31, natural size), but, as a 
rule, these pupse are the lightest of all in both these respects. The lens, however, 
shows the existence of minute dots in all cases, although in the more extreme forms 
very few minute points can be detected by the naked eye, and there is no trace of the 
black markings even upon the rostrum. It is very common in the extreme forms of 
this degree, and in the lightest of the last degree, for the median and lateral ridges 
and the extremities of the body to be of a distinct pink tinge. 
Series 1.—Larva: subjected to Various Colours. 
I. Black. 
A. 
On September 13, 10 mature larvse of P. brassicce and four of P. rapes were 
placed in a cylinder 7 centimetres in internal diameter and ] 8 centimetres in 
height, lined entirely with thick blackened paper, and with a roof and floor of the 
same material. Thus the glass was entirely concealed, and the larvae were everywhere 
surrounded by a black background, while light was almost completely excluded. 
In the following Tables the larvae of Pieris brassicce are indicated by the letters P. B., 
and those of Pieris rapes by P. P. Periodical inspection gave the following data for 
estimating the length of the period preparatory to pupation, &c. : — 
Sept. 13, 9.30 a.m. 
Experiment began. 
„ 15, evening 
2 larvae, P. B., girdled ...... 
Stage Ill. at least 20-30 hours in 
these cases. 
„ 16, 6.15 p.m. 
1 P. B. pupated, and 2 girdled; 1 P. R. 
girdled 
About 70 hours for the whole prepara¬ 
tory period of the 1 pupated. 
„ 17, 7.30 p.m. 
2 P. B. pupated, and 1 P. R.; 7 P. B. 
girdled 
Between 90 and 100 hours for the 
whole period of the 2 pupated. 
„ 18, 7.50 p.m. 
6 P. B. and 1 P. R. pupated; 3 P. B 
and 1 P. R. girdled 
Over 100 hours for the whole period of 
some of these ; others may not have 
begun Stage I. directly they were 
put in the cylinder. 
„ 19, 8.47 p.m. 
7 P. B. and 2 P. R. pupated. 
Results .—Except when it is otherwise stated, the pupse were all compared together 
on January 23-26, 1887, and, as nearly the whole of them were thus placed together, 
the results are very trustworthy. 
Eight pupse of P. brassicce were alive when the comparison took place. 
5 were fairly crowded on the roof; of these. . 
3 were scattered over the side, towards the 
upper part, but uot crowded. 
2 were (1), a, the ground-colour almost entirely grey. 
3 „ (1), ( 3 , 1 with a yellowish-green tinge, and 
2 faintly orange. 
1 was (1), a, with a faint orange tinge. 
2 were (1), /3, both greenish. 
3 G 2 
