PHYCIODES I., II. 
produced artificially. It was taken at Grimsby, Ontario, and probably owes its 
peculiarities to its chrysalis having been frozen soon after it formed. That such 
examples are not frequently seen on the wing may be partly due to the fact that 
chrysalids of tender age subjected to severe cold are usually killed by it. Fig. 
13 is the likeness of an aberration sent me by Professor Garman, and taken at 
Normal, Illinois. 
Dorfmeister, who experimented on the effect of cold upon the chrysalids of 
butterflies, as related by Dr. Weismann, was led to believe that temperature ex¬ 
erts the greatest influence during the turning into chrysalis, but nearly as much 
shortly after that time. By my experiments it would appear unnecessary that 
cold should be applied before the chrysalis has fully hardened in order to effect 
a change of form, and this requires a longer or shorter time in different species, 
but never more than a few hours. In 1876, the chrysalids of Tharos, which 
were exposed at from six to nine hours after forming, changed as completely as 
those at from three to six hours. In 1877, all which were exposed at from one 
to nine hours changed, while some which were exposed at from thirty to sixty 
minutes were not changed at all, though others were. The turning-point is evi¬ 
dently not at or immediately after the forming of the chrysalis. The cold com¬ 
pletely retards the development of the butterfly, and at least the full natural 
chrysalis period passes after removal from ice before the butterfly emerges. This 
has happened in every case under observation, even when from insufficient or 
intermittent cold no change of form has resulted. 
The change of form seems to be almost wholly a matter of coloration, for the 
shape of the wings is not altered. The natural shape of Walshii is quite differ¬ 
ent from that of Marcellus , but when the latter by application of cold is forced 
to assume the markings of Walsliii, it retains its own shape nevertheless. In 
the other species experimented on there is no difference in shape between the 
winter and summer forms. The coloring process in all chrysalids does not set in 
till just before the butterfly emerges, no matter how protracted the pupal period. 
It may be days or weeks, and in the case of over-wintering chrysalids, it is many 
months. On removing one of the wing cases, soon after the chrysalis is formed, 
the wing is seen to be a delicate, transparent, colorless membrane, crossed by 
white veins. Very gradually this membrane thickens, losing its transparency, 
and becomes of a dull white. A few hours, or one or two days, before the close 
of the period, it grows darker, then a faint discoloration comes on, and the pat¬ 
tern begins to show itself, the colors becoming strong and the markings w r ell- 
defined as the disclosure is about to take place. On removing the wing case 
from a chrysalis just off ice, the wing presents itself in its colorless and trans¬ 
parent stage ; that is, the development has been arrested by the cold, and the 
