LEPIDGPTEROUS PUP^E AND THEIR SURROUNDING SURFACES. 
423 
Sept. 14, 9.15 p.m. . 
„ 15, EVENING . 
Experiment began. 
1 P. B. girdled. 
„ 16, 7 p.m. . | 
4 P. B. girdled, and the P. R. pupated "1 
The P. R. must bave passed about 40 hrs. 
some time > 
4 more P. B. and 4 P. R. added 
in tke period if it began when larva 
was placed in the cylinder. 
„ 17, 7.25 p.m. . 
3 P. B. pupated, and 1 P. R.; 3 P. B. 
and 1 P. R. girdled 
Under 72 hrs. in the period if it began 
with the experiment. 
„ 18, 8.30 p.m. . 
6 P. B. pupated, and 1 P. R.; 2 P. B. 
and 1 P. R. girdled 
Under 48 hrs. for some of these if the 
period began with the experiment. 
„ 19, 8.55 p.m. . 
6 P. B. pupated, and 2 P. R. ; 2 P. B. 
girdled. 
Results. —Seven living pupae of P. brassicce were obtained :— 
6 were crowded on the side near the roof, 
and of these.5 were (2), all with the characteristic opaque yellowish 
ground-colour, mottled with green, and small 
black patches and spots. One was yellower 
than the others, with less of the green mottling. 
1 was (3), rather greyer-green than usual, and rather 
larger black patches. 
1 pupa was more isolated, and an outlying 
member of the group described above: it was (1), (i, with a rather brighter and more distinct 
yellowish-green ground-colour than usual, 
because the grey was less pronounced. 
Two living pupae of P. rapes were similarly compared, both being in the group of six 
P. brassicce described above ; and 
Of these, 1 was a (3), light for this degree, with a faint yellowish-green ground-colour, and much less 
of the grey dusting than usual posteriorly; normal anteriorly. 
1 was a (4), with very little pigment and very pale pinkish ground-colour. k 
It is very remarkable that the green surroundings should have shown less influence 
than orange or yellow in the production of varieties which by their colour are especially 
protected upon the first-named colour. It must be remembered, however, that the 
conditions of experiment were different, tissue-paper being used in this case, and highly 
illuminated opaque reflecting surfaces in the former. Nevertheless, tissue-paper has 
been shown to produce marked effects with V. Io, and it certainly made a bright green 
background. And here, although the effects seem small when compared with those of 
orange, they are in reality considerable, and are all in a protective direction. 
B. 
September 15.—10 larvse of P. brassicce and 13 of P. rapes were placed in a glass 
cylinder (7‘5 centimetres in internal diameter and 17"25 centimetres in height) com¬ 
pletely covered externally with one layer of green tissue-paper, and with a roof and 
floor of the same material. The P. rapce had been found upon mignonette, and were 
mostly full-fed, but after September 16 they were fed upon cabbage. The following 
notes were made :—• 
