34 
THK entomologist’s RECORD. 
will not apply in all cases. The imagines of our dark Alpine 
species appear in January and February, which are the clearest 
and hottest months in the year. Nothing is absolutely known 
of their economy and habits, yet we may surmise that the eggs 
are deposited soon after emergence, and the larvae feed up in 
March and April. In the latter months the autumnal rains 
set in, which are greater and more prolonged on the Ranges 
than in the lower country. It must be admitted that larvae 
feeding on high altitudes are subjected to a lower temperature ; 
but it will also be observed that they are subjected in our 
climate to a much greater degree of moisture than other or 
allied species existing on the lowlands. About the end of 
April or beginning of May, the snow begins to cover the higher 
parts of the Ranges, and continues, more or less, to fall until 
September, when the warm north-west wind generally begins 
to blow and melt it off the Ranges. The pupae thus deeply 
buried in snow through the winter, would experience no more 
cold on those high regions than other pupae exposed to all 
weathers on the plains, on which snow scarcely ever falls. 
The north-west winds which begin to blow in September, are at 
first slightly chilly, owing to their traversing the snow-fields of 
the Alps. As the snow lessens in quantity, the wind blows 
hotter and drier across the plains, causing the snow-fed rivers 
to flood, although the wind is cool before it impinges on the 
western summits of the Ranges. It absorbs great moisture in 
crossing the snow fields, which is frequently condensed in 
heavy rain showers over the lower hills and downs, and along 
the bases of the mountains ; here the lepidoptera are invariably 
darker than on the open plains, where the warm north-west 
rains rarely ever reach. The physical features of the country 
I have described, namely, high mountain ranges and extensive 
plains occurring contiguously, differ greatly from any districts 
as yet mentioned by Mr. Tutt, where he states melanism 
occurs. Nevertheless the cause of melanism and melanchro- 
ism appears to be identical in all cases. The very reverse 
meteorological conditions of climate are frequently observed 
here on the same day, for, although the day may be dry and 
hot on the plains, the Ranges are at the same time enveloped 
for days together in dense aqueous clouds condensing great 
moisture (see remarks by Professor Schbyen of Christiania, 
quoted by Mr. Tutt, Ent. Record, vol. i., 53). 
“ The elucidation of any cause producing variation in animals 
requires very careful study, and any theory advanced to 
