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XV. Temperature Hxperiments in 1893 on several species 
of Vanessa and other Lepidoptera. By Fxreperic 
MerririEbp, F.E.S. 
[Read March 14th, 1894.] 
PuaTE IX, 
In my last paper (Trans. Ent. Soc. Lond. 1893, p. 57) I 
described some experiments on pupex of P. napi, off- 
spring of the spring emergence, and mentioned that I 
had some pup offspring of the summer emergence. 
The parents consisted of two males and two females, 
taken at Hailsham, and kindly sent to me by Mr. Vine 
on the 30th July, and two females taken at Petworth on 
the 5th August, and kindly given to me by Mr. Fletcher. 
From these I had several hundred eggs, which were laid 
much more freely on cardamines than on cabbage, 
though the larva seemed to feed as willingly on the 
latter as on the former. 
Early in September nearly all pupated. Ten were 
placed at 90° for ten days, a period amply sufficient to 
have caused their emergence had they belonged to the 
earlier brood, but it produced no effect either on the date 
of their emergence, when afterwards placed out of doors, 
or on their markings or colouring. The rest were kept 
out of doors. Some were forced about the middle of 
February, and some more early in March, emerging in 
from eight to seventeen days. The difference in appear- 
ance between these and the rest, which emerged out of 
doors between the 20th April and 9th May (except one 
which emerged 6th June), is the same in kind (though 
somewhat less in degree) as the difference between 
those of the summer emergence, which were forced all 
_ through, and those of that emergence which were cooled 
for the greater portion of their pupal period, as 
described Trans. Ent. Soc. Lond. 1893, p. 57. 
Consequently I may apply to the winter pupating 
brood the general remark made there, as to the brood 
which pupates in the summer, viz., that a part but not 
all of the characteristic seasonal colouring of this species 
depends on the temperature to which the individual is 
TRANS. ENT. SOC. LOND, 1894,—PaRT III. (SEPT.) 25 
