17 
germative moths, notably Se/enia IJ/lustraria, confirmed thesc 
results in the main, but established some results which Weis- 
mann’s explanation did not cover. They proved that, by warming 
the pupa of the Winter form shortly before its emergence, the 
perfect insect could be made in colouring, but not in marking, to 
approach the Summer form, also that certain single brooded species, 
€.g., Ennomos Autumnaria had their colouring much affected by 
temperature at their late pupal stage. In both the species 
experimented on the tendency of the lower temperature was to 
cause a darker colouring. ‘The difference in appearance caused 
by the temperature applied was often conspicuous, and a range 
between 57° and 80° Fahr. was sufficient. A ‘‘ warm atmospheric 
wave,” coming in and lasting for only a few days, if it happened 
to come just at the right stage of pupal development, could not 
fail to affect the colouring of some species in a state of nature. 
He thought it probable that some supposed climatic or seasonal 
races would prove to be in fact temperature varieties of the indi- 
vidual, and on the now generally accepted view that the changes 
which an individual went through in its embryonic stages were an 
epitome of the changes the species, genus, or family had gone 
through in the course of its evolution, experiments of this kind, 
if Prof. Weismann’s theory of reversion were accepted, might throw 
light on the process of evolution of the complex markings and 
colouring of the wings of some of the Lepidoptera. The change 
in markings appeared to require a lengthened application of 
temperature during the earlier pupal stages, whereas the change 
in general colouring was caused by a comparatively brief exposure. 
during the penultimate stage, z.e., that immediately preceding the 
last stage of all, in which the colouring of the perfect insect can 
be seen through the semi-transparent pupa case. Applying the 
knowledge gained by his experiments, he had obtained from the 
same batch of eggs of the Summer brood four forms of the 
perfect insect, viz.: (1) Summer markings and colouring ; 
(2) Summer markings and Winter colouring; (3) Winter mark- 
ings and colouring ; and (4) Winter markings and Summer 
colouring ; and he exhibited specimens and enlarged coloured 
photographs of each. 
