BUTTERFLY COLLECTING IN INDIA. 507 
species more than in others ; they are usually very different to the parent form. 
This class of variation has attracted a great deal of interest of late years and 
forms more or less the basis of the theory known as Mendelism, which by 
experiments on domesticated animals and plants has been proved to be a law 
and no mere theory. It is supposed by some authorities that it is these sports 
that give rise to new species in Nature. 
14. Seasonal variation, as one might expect, is most marked in Indian 
butterflies. In any species that has two or more broods during the year, 
differences to a greater orless degree are to be found between the broods and, 
as arule, the greater the local difference of season, the more apparent the 
influence on the wings of the butterfly. In some of the Satyrids the differences 
between the undersides of the two seasonal forms is startling and for many years 
they were regarded as different species : in the instances to which I am referring 
locality does not appear to affect the intensity of the dimorphism. In the dry 
season form the underside exactly resembles a dried leaf, while in the wet season 
form the underside is evenly striated and bears a row of eyes along the 
border. The reasons for seasonal variation are probably to be ascertained by 
a close investigation of the caterpillar stage and perhaps are due to the seasonal 
variation in the food plant ; in some species it is possible that the characteristic 
has been inherited from bygone days and still remains though the original causes 
have disappeared. 
15. Geographical variation presents a most interesting field for investigation 
and it is not unlikely that in geographical variation combined with Mendelism 
will be found the solution to the formation of species. As pointed out in para. 
11 Nature is always urging a species to enlarge its sphere of action and, if a species 
spreads to a district which differs in climate or other particulars from its original 
home, it may, if it is a decadent species fail to establish itself, but if it can contend 
with the change in the caterpillar food, the new enemies to be encountered with 
and the new climatic conditions, it will form a new colony. The different condi- 
tions may soon have an influence on the appearance, habits, etc. of the butterfly 
and a definite, easily distinguished, geographical race may become established. 
If the species is given to produce aberrations or become so by reason of the new 
conditions, as is quite probable, the sport, which is a recessive under Mendel’s 
law in the original home may become the dominant and, gradually swamping 
the normal form, establish a new species. If the habitat of the parent species 
and of the colonists is not separated by an impassable barrier, such as plains in 
the case of hill species or hills in the case of plains species or desert or sea, it 
is quite likely that the races will remain closely allied and can be graded in a long 
series. If, however, a barrier exists or becomes formed by geological changes, 
the two races will gradually become more and more different as the centuries roll 
on, and should the changes in the earth surface ever bring them together again, 
they may be unable to interbreed and therefore must be regarded as species. 
Increase in elevation appears to have a considerable effect and I am not at all 
sure whether certain closely allied so-called species, found at different elevations, 
are not really conspecific, a certain feature being dominant in one area and re- 
cessive in another. Some of the inhabitants of the Himalayas differ on every 
watershed or in every large valley. There is a certain large Papilionid, memnon 
by name, that presents several remarkable features, not the least of which is 
that it possesses three forms of female, one of which is tailed, while the male and 
the other two females are tailless. Now in South India and Ceylon there flies 
an allied species called polymnestor, where the sexes are nearly alike, bus are 
widely different from memnon, in that they bear a broad pale blue band above. 
Now memnon and polymnestor meet in the lowlands of Sikkim, but do not 
appear to trespass on each other’s boundaries ; yet certain known aberrations 
of memnon show a marked resemblance to polymnestor. I would not be at all 
surprised to hear that they were conspecific and that each is the dominant in 
