ee CC EIR. 
EXPERIMENTS UPON THE EFFECT OF COLD .APPLIED TO CHRYS- 
ALIDS OF BUTTERFLIES. 
BY WILLIAM HENRY EDWARDS, COALBURGH, W. VA. 
1. In May 1878, I placed many chrys- 
alids of Papilio ajax, from eggs laid by 
form walshii, in the ice box. The youngest 
were aged but 10 to 15 minutes after pu- 
pation and were still soft ; others were add- 
ed at intervals up to the age of 24 hours 
(the chrysalis is hard at about 12 hours), 
and others yet at 2 days, 3 days and so 
on to 8 days after pupation. All were re- 
moved from the box on the same day. The 
exposure had been from 19 to 5 days, those 
chrysalids which were put in latest gener- 
ally having had the shortest exposure. I 
wished to determine, if possible, whether, 
in order to effect any change, it was neces- 
sary that cold should be applied immediate- 
ly after pupation, or if one or several days 
might intervene between pupation and ic- 
- ing. Inasmuch asno color begins to show 
itself in the pupa till a few hours, or at 
most a day or two, before the butterfly 
emerges, I thought it possible that cold 
applied shortly before that time might be 
quite as effective as if applied earlier, and 
particularly very soon after pupation. The 
result was that more than half the young- 
est and immature chrysalids died; one 
which had been exposed at 10 minutes 
after pupation, two at 1 hour, one at 2 
hours, two at 3 hours. On the other hand, 
one exposed at 15 minutes, one at 2 hours, 
and one at 12 hours, produced butterflies. 
The temperature was from 32° to 34° F. 
[0° to 1° C.] most of the time, rising some- 
what daily as the ice melted. The nor- 
mal chrysalis period in this species is from 
11 to 14 days, in case the butterfly emerges 
the same season, but now aud then a single 
butterfly will emerge several weeks after 
pupation. The latter is an uncommon oc- 
currence, however, as usually the chrysa- 
lids which do not give imagos within 14 
days retain them till the following spring. 
The form which would naturally emerge 
the first season from these chrysalids is 
marcellus, but all the overwintering chrys-, 
alids would produce telamonides or walshii, 
which latter are the winter forms of the 
species. If then, from the chrysalids sub- 
jected to cold, the winter form should 
emerge the same season, it would be owing 
to the exposure to cold. 
On the 14th day after taking the chrysa- 
lids from the ice, one telamonides emerged, 
from a chrysalis placed in the ice box 3 
days after pupation, and kept there 16 days. 
