492 JOURNAL, BOMBAY NATURAL HISTORY SOCIETY, Vol. VIII. 
the hilly districts of that country the rains sometimes continue till 
well into December. The same limitations would also apply fairly 
well to the whole of Hastern and Southern India, but in the dry tracts 
of the North-west the rains are of shorter duration and are less con- 
tinuous ; consequently, rainy-season forms are scarce, and dry-season 
ones are much more pronounced. 
It must also be borne in mind that these seasonal races are not con- 
fined to two clearly defined forms, 7.e., a rainy-season, and a dry-season 
form, but that in most species there are not only two very distinct-looking 
forms which represent the extremes of the two seasonal races, 
and which prevail in the rainy and dry-seasons respectively, but 
also numerous intermediates linking these extremes together, many of 
these intermediates having received names. A further point to be 
noticed is that these forms themselves vary according to the vegetation 
and rainfall, so that the extreme of the rainy-season form from a dis- 
trict where the rainfall is great and the vegetation dense is much more 
pronounced than the extreme of the rainy-season form from a district 
with slight rainfall and sparse vegetation ; and these differences are 
even more marked in the dry-season forms ; while in all genera the 
dry-season forms are asa rule smaller than the rainy-season forms. 
It is therefore an extremely difficult matter for home naturalists to 
work out correctly questions of seasonal variation, more especially as 
it is their usual practice to ignore the observations of working col- 
lectors who see the species in life and note the forms changing month 
by month from one extreme to the other. 
The question as to what forms should be granted specific rank is 
one which is continually under dispute, and it is impossible to lay 
down any hard or fast rule which could be applied to all families and 
genera of butterflies, as in some genera we find absolutely fixed types 
which are constant throughout their range, while in other genera the 
- difficulty is to find two individuals which are absolutely identical. 
The most obvious way out of the difficulty is to give sub-specific names 
to forms which appear to be constant but nevertheless to be too closely 
allied to some other form to be considered a distinct species, and this 
practice has been adopted to a limited extent by Mr. Scudder in his 
“ Butterflies of the Eastern United States,” and I consider it very pro- 
bable that it will be found necessary hereafter to adopt some similar 
