x¢cli, xcili] cr el) 
““(2) Nor is it easy to consider melanism as a direct 
consequence of high altitude, for here again it is often only 
the one sex that is affected, as in G. bryonix, Besides this, 
female G. napi of the ordinary kind may be found in the same 
localities as G@. bryonix ; and ‘ white’ butterflies which are met 
with at enormously high altitudes, such as Baltia shawti, Bates, 
$ in Central Asia and Phulia nymphula, Blanch., in the 
Andes, are by no means melanic. Again, the female of 
Tatochila demodice, Blanch., shows dark pigmentation whether 
taken at high altitudes or at the sea-level. 
(3) There is obviously a strong connection between 
seasonal conditions and melanism. This is clearly shown by 
the series of seasonal forms in the present exhibit. As a rule, 
the deeply-pigmented form belongs to the wet season, and the 
paler form to the dry. But here again, if we attempt to make 
wet-season conditions a direct cause of melanism, we are met 
by the fact that sometimes the same conditions are associated 
with an exactly opposite result. The instance of Precis octavia- 
natalensis and sesamus will occur to every one as a case in 
point; but without travelling beyond the Pierine we have 
only to compare the under-sides of, say, Lvias pyrene, Linn., ¢ , 
wet and dry, or of Zerias senegalensis, Boisd., ¢ wet and dry, 
to see that an increase of dark pigmentation, whether in a 
diffused or concentrated form, may characterise a dry-season 
phase as opposed to a wet one. A further difficulty is that 
dark pigmentation appears in some instances (as in Polyom- 
matus phlxas, var. eleus) to be an accompaniment of heat, in 
others (as in Vanessa urtice, var. polaris) of cold. 
(4) Lastly, with regard to sex. It is no doubt true that in 
the majority of instances the female shows a darker coloration 
than the male. This comes out well in many of the specimens 
exhibited. But it is not difficult to find examples of the 
reverse condition, where the female possesses less dark 
pigment than her mate. This is the case, for instance, with 
some forms of Colias eurytheme, Boisd., and with Dismorphia 
thermesia, Godt. 
“Tt seems therefore difficult to attribute melanism, or the 
tendency towards that condition, to the immediate action of 
either geographical or seasonal conditions or to the: direct 
