Gp y09y.°) 
Il. The effects of temperature in the pupal stage on the 
colouring of Pieris napi, Vanessa atalanta, Chry- 
sophanus phloeas, and Ephyra punctaria. by 
FREDERIC MERRIFIELD, F'.E.S. 
[Read December 7th, 1892. ] 
Puate LV. 
I wish to premise that nothing approaching to the 
amount of variation one would find in large collections 
can be expected as the result of these temperature 
experiments. In such collections we find the results of 
a combination of different causes, including individual 
tendencies to sport, and they contain selections from 
thousands of individuals of different broods and from 
different localities, the object of most collectors being 
to assemble the most abnormal specimens they can meet 
with. My object, on the contrary, has been to obtain 
sets of individuals naturally as much alike as possible, 
so as to make sure that any changes were the results of 
the different temperature conditions applied; and to 
secure this natural invariableness I always, where it was 
possible, obtained a set from the same parents. Not- 
withstanding all the consequent limitations in result, I 
think there are some varieties, plainly attributable to 
temperature, among the specimens I exhibit this even- 
ing, that would be noticed in any cabinet. 
Let me further remark that when in the course of this 
paper I speak of certain of my artificial temperatures as 
corresponding with the temperature of certain seasons 
or countries, | am well aware that the correspondence is 
in some cases incomplete. Natural temperatures are so 
fluctuating that it is difficult to imitate them artificially, 
but I do not think the difference in this respect is for 
my purposes an important one, for in many instances I 
have used both artificially equable, and naturally fluc- 
tuating temperatures, and in these cases I have in- 
variably found that a fluctuating temperature produced 
results similar to those obtained from an equable 
TRANS. ENT. SOC. LOND. 1893 —PaRTI. (MARCH.) 
