PSYCHE. 
ened, and the growth of the organs of the 
pupa probably then begins, and their direc- 
tion may best be turned by the cold then 
applied. 
3. The effect of the cold is to albinize 
the butterfly, the black area being con- 
stantly reduced. 
4. Cold has failed to change the shape 
of the wings, its influence being confined 
to coloration and markings; the frontal} 
hairs of the head have also been changed ; 
and the sexes are equally susceptible. 
5. Grapta interrogationis. 14 days 
exposure after the chrysalids have hard- 
ened, has been found suflicient to produce 
changes; and the females were most sus- 
ceptible to the influence of cold. 
6. With different species the degree of 
temperature required to produce the most 
decided change varies. I have succeeded 
best with Phyciodes tharos, at 40° F. 
[4.4° C.]. At 32° F. [0° C.] have de- 
stroyed many Grapta chrysalids, but this 
may have been principally because the 
chrysalis was too tender when exposed. 
19 
With P. ajax 32° to 40° F. [0° to 4.4° C.] 
seems a proper temperature. 
My experiments with Ph. tharos are 
given in Can. Entom., v. 9, p. 4, and p. 
204-206. Also in Butterflies of N. A.,, 
ve 2,. pt. 7. 
change was brought about, and every but- 
terfly emerged in the winter form. 'Temp- 
erature about 40° F. [4.4° C.], and con- 
tinued for 7 days, the chrysalids being 3, 
6, 9 hours old when exposed, and before 
several had hardened. In the second ex- 
periment, the temperature was about 32° 
F. [0° C.]; the chrysalids were 10 min- 
utes to 9 hours old, and the exposure was 
about 20 days. It was found that the but- 
terflies emerging from chrysalids which 
had been from 1 to 9 hours old were com- 
pletely changed; some which had been 
from 30 to 60 minutes old were not 
changed, while others of same lot were 
greatly suffused. I concluded that with 
this species it was not necessary that cold 
should be applied after the chrysalids had 
hardened, in order to change the form. 
In the former, a complete 
REVIEWS. 
ProressorR Epuarp Branpv’s interest- 
ing papers upon the nervous system of in- 
sects, which appeared during 1878 and 
1879 [see Rec., nos. 1451-1458] in the 
Horae Societatis Entomologicae Rossicae, 
- are yaluable additions to the literature of 
the subject. The amount of research upon 
which the author’s conclusions are based, 
can be best understood, perhaps, by con- 
sidering that Professor Brandt examined 
the nervous system of nearly a thousand 
species of adult insects, and of about one 
hundred and twenty-five species of larvae, 
and that he studied the metamorphoses of 
the nervous system in more than fifty spe- 
cies. Up to the time of appearance of 
Professor Brandt’s papers but little had 
been published upon this subject; for ex- 
ample, the metamorphoses of the nervous 
system had been traced in only eight spe- 
cies (four lepidoptera and four coleoptera). 
Many important facts were ascertained in 
his studies, and the papers, published both 
in German and in Russian, and fully il- 
lustrated with photolithographic plates, pre- 
sent the facts in a systematic and carefully 
condensed form. @. D. 
