78 
THE entomologist’s RECORD. 
large quantity of smoke, fumes, etc. which of late years have 
been developed in Southern Lancashire: — “This may have 
effected a change in the climate, as well as deposited on the 
leaves of trees and foodplants of Lepidoptera, matter which 
may possibly cause some white insects to become gradually 
black, through being swallowed by the larvae with their food.” 
This, I believe, would have no effect on the larvae themselves, 
as far as colour is concerned. Phytophagic varieties are, as I 
have before repeated, mainly ^ those of size, and I fail to see, 
on ordinary physiological grounds, how the colour could be 
affected in this way. Dr. White also writes in a very 
interesting paragraph on this subject {Entomologist, x., p. 
128): — “In the same way, the foodplants may, on certain 
soils, affect the colours of the insects ; but if it is so at all, 
it is probable only in a few cases ; the influence of the food- 
plant upon the colours of insects seems not to be very great.” 
Mr. Prest, dealing with the same subject {Entomologist, x., p. 
130) writes : — “ I do not think that either chemical fumes, or 
coal-smoke can have any influence in our district of York- 
shire.” He then runs through a list of species which are 
melanic in Yorkshire, and writes : — “ From these facts I form 
my opinion that soil in its action upon the foodplant has 
more to do with variation — heredity or otherwise — and 
melanism, than either chemical fumes or coal-smoke.” At 
p. 131, Mr. E. K. Robinson looks upon the foodplant as 
being the main agent, and instances the Leucaniidcs in 
marshes, entirely overlooking the protective resemblance these 
species bear to the nodes on the reeds, etc., on which they 
rest head downwards. He also states as a fact that “ food 
in a semi-withered or dry condition produces moths of small 
size; for Amphidasys betularia thus fed becomes in a few 
generations completely black ; and by the same means the 
proportion of black to white in Abraxas grossulariata and of 
brown and black to white and red in Clielonia caia, is largely 
increased.” I do not know that there is the slightest founda- 
tion in fact for supposing that any of the three species 
mentioned are influenced directly in the way suggested by 
Mr. Robinson, nor does he offer any further proof of his state- 
ments, other than thus giving most positively his own opinion 
on the point. He sums up his arguments as follows: — “ (i). 
A large percentage of water in the tissues of the foodplant 
^ Unless the species feeds on different foodplants which have a very different 
chemical composition. — J.W.T, 
