xciv, xcv| (13: *) 
upon the individual, nor even that such direct effect may under 
some circumstances reappear in the offspring. Weismann’s 
results with P. phixas, Fischer’s with Arctia caja, and others 
on record (see Schneider, ‘“ Einfiihrung in die Deszendenz- 
theorie,” 1906, p. 113, etc.) seem to demonstrate the possibility 
of such apparent transmission. But this phenomenon of the 
diverse effect upon the two surfaces, together with the other 
considerations already brought forward, appears to make 
strongly against the hypothesis of a direct effect; and to 
favour, as far as it goes, the view that such changes as these 
are adaptive. 
“ A further point of interest arises in connection with the 
common absence of dark pigmentation on the under-side of wet- 
season forms, even when the upper surface is strongly melanic. 
It is this: that on comparing the seasonal phases of such forms 
we are often led to the conclusion that so far as the upper-side 
is concerned the wet-season form is better protected, but with 
regard to the lower-side the corresponding dry-season phase, 
being cryptically coloured, has the advantage. This may mean 
that the wet-season form requires more protection during flight, 
and the dry-season form during repose ; and this again may 
point to the fact that it is such enemies as attack butterflies at 
rest (for example, lizards) that are especially dangerous during 
the drier part of the year. 
“ Whether the duskiness so often met with in arctic and 
mountain forms can at present be explained as an adaptation, 
is perhaps doubtful; though there seems to be no reason why 
Lord Walsingham’s suggestion of its relation to the power of 
heat-absorption should not be correct. In such cases of the 
development of dark pigment as we see in females of Mylothris 
lorena, Hew., I. pyrrha, Fabr., Pieris demophile, Clerck., 
P. viardi, Boisd., P. locusta, Feld., P. tithoreides, Butl., etc., 
to which may probably be added the wet-season Glutophiissa 
saba @ (see Trimen, Proc. Ent. Soc. Lond., 1881, p. viii), the 
influence at work is that of mimicry, and the result clearly 
takes rank as an adaptation. 
“The occasional predominance of dark pigment in the males 
as compared with their mates is apt to show itself in the form 
of distinct and definite areas—not in that of suffusion, A 
