76 
senting the earlier broods. Of the 69 
pupae of June 1879 (Psycne, p. 4), 34 
yielded butterflies the same season; and 
of the 35 of same lot, which were iced, 
16 emerged the same season. 
By this it does not appear that cold made 
any butterfly emerge in 1879 whose natural 
term was 1880. It is impossible to be 
absolutely certain of this fact, but the 
probability is very strong that the change 
produced by cold was in coloration, or in 
the clothing (as in the frontal hairs). What 
PSYCHE. 
76 [0.53] [average, 0.52], the first repre-. 
should have emerged in 1879 as the sum- 
mer form did so emerge in shape, but pre- 
sented the coloration of the winter form. 
I call to mind only two species of North 
American butterflies in which there is a 
decided difference of shape between the 
winter and summer forms, namely, P. ajax 
and Grapta interrogationis. In other spe- 
cies, as the shape is identical in both forms, 
it could not be ascertained whether the ap- 
plication of cold had affected anything be- 
yond the coloration or clothing. 
LARVAE OF THE FAMILY PYROCHROIDAE. 
BY HENRY LORING MOODY, MALDEN, MASS. 
The larva of Dendroides canadensis is a 
type of the larvae of the Pyrochroidae, of 
which family I have bred four species, 
namely, D. canadensis, D. concolor, Pyro- 
chroa flabellata, and Schizotus cervicalis. 
These larvae all have a much flattened and 
appressed body, a vertically compressed 
head slightly broader than the prothorax, 
and, attached to the final segment, a corne- 
ous plate, produced into two distant, hori- 
zontal, more or less curved processes. 
Three of the species are honey yellow, and 
approximate very nearly in size. The 
fourth, Schizotus cervicalis, is of a smoky 
tint andsmaller. The color separates this 
last from the other three, which may be sep- 
arated from each other by the corneous 
plate and processes. In D. canadensis the 
processes are nearly one third longer than 
the basal portion, are rather slender, regu- 
larly though moderately curved inward, and 
have fine granulations which are more nu- 
merous toward the tips. Between these 
processes at their bases, are found two 
small blind cavities, or cul-de-sacs, which 
do not appear at all when looked for from 
above. 
In D. concolor the processes are stouter, 
nearly straight, and hardly longer than the 
basal portion. The tips are obliquely cut 
off on their inner side. The cul-de-sacs 
between them are larger than in D. cana- 
densis, and have at their lower side a 
slightly projecting lip, which can be seen 
from above. The modification of these 
characters in P. flabellata is more marked ; 
the processes are straight on the inner 
edge, still shorter in proportion to the base 
than in the previous species, and the gran- 
ulations are much stronger. On the under 
side of each process, near the base, there 
is a tooth-like projection, and the outer 
edge at the base has two such projections, 
one smaller than the other. The cul-de- 
sacs are very large, with the projecting lip 
prominent and emarginate at the middle. 
In conclusion a word in regard to the eu- 
rious cul-de-sacs. They are deep, and sug- 
gest a possible organic use; but thus far, 
though I have carefully dissected for the 
purpose, I have not found that they are in 
any way connected with the internal organs, 
or have any opening into the interior of 
the body. 
