428 
LEPIDOPTERA. 
identical; it is evident that every species varies, that given a large number 
of variable specimens it is difficult to group them if there are any inter¬ 
mediates, and finally that, since this depends entirely on the judgment 
of the individual, the views of variable individuals will differ; we must then 
have recourse to the only test, namely, breeding from eggs laid by dis¬ 
tinct females ; if we find that out of one female’s eggs we get all the varie¬ 
ties, then all fall into one species ; when this does not occur, but one batch 
of eggs gives only one variety, and another a second, we are further 
towards the truth, and by further breeding and judicious attempts at 
coupling, we can separate our species with some distinctness. This is 
what requires to be done for many forms of Rhopalocera, and will 
eventually have to be done in the case of many species of other groups, 
when these come to be as well known as the butterflies. 
Castalius ethion, Doubl., and C. rosimon, Fabr., are also recorded by 
Bingham as widespread in India, feeding also on the ber. 
Polyommatus bceticus, Linn., is referred to by de Rh<'Philippe as 
migrating yearly in swarms from Lucknow to the hills in the early hot 
weather (Journ. Bombay Nat. Hist. Soc. XIY, p. 488). Probably many 
more species have this habit in sub-Himalayan localities and the cold 
weather fauna of the Gangetic plain may be partly composed of such 
migrating insects. De Niceville records rearing this on the flowers and 
pods of Crotalaria calycina. 
Virachola isocrates, Fabr., is the most important economically of 
the butterflies, perhaps the only one that is constantly and regularly 
injurious. The male is a beautiful glossy violet blue above, the forewing 
with an indistinct ochreous spot; the female is violet brown above, the 
ochreous spot more distinct. This insect has been described and figured 
several times ; the student should read the delightful account of West- 
wood, reprinted in de Niceville’s Butterflies of India, III, p. 478. The 
larva feeds on the fruit of guava, pomegranate, etc. F. perse, Hewits., 
also occurs throughout India, both sexes being black above, with blue 
(not metallic) on the basal area of forewing and disc of hindwing 
Aitken records it as feeding on the fruit of the Ghela (R audio 
dumetorum). 
