on the colouring of Pieris napi, ce. 65 
It seems to follow that in this species the principal 
effects on colour, &c., are produced not by long exposure to 
severe cold, but by exposure, during the period when the 
active part of the pupal stages has begun, to (1) great 
heat, producing duskiness, or (2) moderate cold, pro- 
ducing vividness and intensity of colouring in both the 
coppery and the dark parts, smallness of spots, and 
great enlargement of the copper band on the hind 
wings. 
These experiments show, I think, that the difference 
in appearance between phlwus from Southern Europe 
and phleas from England is not necessarily to be attri- 
buted to the existence of races of different colouring, 
but may be owing to the difference between the tempera- 
tures to which the individuals are exposed in the two 
climates. 
My results show an interesting parallelism with those 
produced, apparently by corresponding natural differences 
of temperature, in the American copper, hypophleas, 
which nearly resembles phlwas in appearance. In this 
species Mr. Scudder remarks that the spring individuals 
[2.e., those which emerge in the colder weather] are of 
a more fiery red, and the orange band on the under sur- 
face of the hind wings is broader ; while in later broods 
(t.e., those emerging in the hot American summer] the 
markings are less vivid and less distinctly marked. He 
adds that there is a longer tooth on the margin of the 
hind wings; this feature appears to exist in a slight 
degree in my phlwas brought out at a high temperature; 
the orange band on the under surface of the hind wings 
is in all mine very inconspicuous. I am indebted to 
Mr. Frohawk for the observation that the markings on 
the under sides of all the wings are considerably stronger 
in those exposed to the high temperature than in those 
at lower temperatures, and in those. at the lowest 
temperature the spots on the fore wings are much 
reduced in size, and on the hind wings are almost 
obliterated. 
HPHYRA PUNCTARIA.—This species is well known for its 
seasonal dimorphism. 
Mr. Fletcher sent me a female taken in the New Forest, which 
reached me 4th June last, with from 140 to 150 of its eggs, 
which were just hatching, and from which I have bred 113 moths, 
besides 7 pup which have gone over till next spring. 21 of these 
TRANS. ENT. SOC. LOND, 18938.—PaRT I. (MARCH.) F 
