the genus Ypthima. 7 
two, or three) gives us well-defined minor groups which 
are easy of recognition, and the total number of the 
ocelli is generally constant in the normal specimens of 
the same species, but the tendency to subdivision of the 
anal ocellus must not be overlooked. The actual num- 
ber of ocelli on the upper side of the hind wing proves 
too liable to vary to be of any value as a_ specific 
character, but their numerical tendency may sometimes 
be used with advantage. 
The diversity. observable in the clasps of forms out- 
wardly nearly alike has almost certainly been brought 
about by natural selection; the possession of a given 
colour or pattern was probably conducive to the preserva- 
tion of the individual, and consequently something very 
nearly approaching community of exterior was oradually 
acquired; whilst the clasp, being merely concerned in 
the reproductive function, and not at all calculated to 
endanger the safety of its possessor by attracting its 
enemies or retarding its escape from them, remained 
unaltered. The species of the Motschulskyi group are 
cases in point, for some of them are really only to be 
determined with certainty after an examination of the 
male genitalia. It is clear that species which it is 
almost impossible to define with accuracy by means of 
external characters may frequently be separated with 
ease by certain characteristic peculiarities in the male 
genitalia, the persistence of which may be proved by 
direct experiment ; it follows, therefore, with regard to 
future descriptions of closely allied species in this genus, 
that one of two things must happen,—either the state- 
ment of diagnostic characters must include an account 
of the male genitalia, or the characters derivable from 
this source must be ignored, with the result that the 
number of insufficient descriptions will be increased 
indefinitely, to the great detriment of scientific progress 
in this particular direction. At the same time, although 
there can be but little doubt that the use of these 
characters will ultimately be greatly extended, there 
undoubtedly exist two grave objections to their general 
adoption ; in the first place, their use entails the exercise 
of a certain amount of patience, combined with some 
manual dexterity; and in the next, there must neces- 
sarily be ‘‘mutilation”’ of specimens (types even occa- 
sionally) by the removal of the extreme apex of the 
