70 
showing that in both species the examples which had been cooled 
were much darkened. 
The general results of his investigations on the changes produced 
by temperature were, he thought, “mainly of three kinds, viz. (1) 
general change, often striking, in the colouring without material 
alteration in the pattern or form of the markings, but often with 
much enhancement or diminution in their intensity; (2) change 
caused by the substitution of scales of a different colour, either 
singly and generally distributed so as to be scattered, or so grouped 
as to form a material change of pattern; (3) change in general 
appearance, caused by imperfection in the development of scales or 
of their pigment. No. 1 seemed a direct effect of temperature, not 
affecting vigorous development. Under No. 2 were to be ranged 
the most radical changes in pattern (as in the extreme case of 
Araschnia levana-prorsa, which had been explained on the theory of 
reversion to an earlier form). In No. 3 the wings were often some- 
what reduced in size, the scales were scanty, irregularly placed, and 
often misshapen and deficient in pigment, the membrane of the wing 
showing between them, so as to give the insect a shining ‘greasy’ 
appearance. Of course, the three were more or less combined in 
many cases. Also he thought that in general the principal changes 
were produced along the margins and at the base and apex, and 
often along the nervures of the wings; perhaps there was some 
connection between this and the fact ascertained and lately published 
by Mr. Mayer, that these were the parts of the wings in which the 
pigment was the last to develop” (‘‘ Proc. Ent. Soc. Lond.,” 1897). 
Mr. Merrifield then went on to briefly describe the more recent 
methods of treatment in the pupal stage, submitting pupeze to inter- 
mittent cold. First he gave the method adopted by Dr. Standfuss, 
under which the insects exhibited by him (Dr. S.) at the Royal 
Society’s Soirée and at the Natural History Museum were produced. 
The pupz had been for five, six, or seven successive days subjected 
to a reduced temperature of from 4° F. to 14° F., kept for one hour 
at the lowest temperature, and then gradually raised to 32° F. The 
results were very remarkable, and in nearly all cases more extreme 
than his own, especially in the fusion together in one very large spot 
of the second and third black costal spots in the Vanessas— V. urtice, 
V.to, and V. polychloros,—and in P. atalanta the total disappearance 
of the large white costal spot. The second method of treatment 
referred to was that of Mr. E. Fischer of Zurich. The pupee in this 
case were for eight successive days reduced three times a day toa 
temperature of 27° F., at which, however, they were only kept some 
few minutes. Then they were raised to about 37° F. The results 
of these experiments appeared to have been as remarkable as those 
produced by Dr. Standfuss’s methods. 
The most sensitive period of the pupal stage was generally the 
early part immediately after it had become tolerably hard ; this in 
warm weather would occur in about twelve hours. But very con- 
