489 
NOTES ON THE SYNONYMY OF SOME SPECIES 
OF INDIAN PIERIN ZL. 
By E. Y. Watson, Inpian Starr Corps. 
(With Plates I and IT.) 
WHILE on leave in England a year or so ago, I endeavoured to 
name my collection of Pverine, and to ascertain the difference 
between the numerous ‘‘ species” described, especially in the genera 
Terias and Izias. From the descriptions alone it is absolutely impos- 
sible to identify specimens, and I found that, even with the type 
specimens before me, the question to which named form any particular 
specimen was referable, was a matter of the greatest uncertainty. In 
either of the above quoted genera for example, we see in the British 
Museum collection a series of specimens arranged above each name, 
the type specimen being frequently included; but on further examina- 
tion of the series it is found that the specimens contained in it are not 
absolutely identical the one with the other or with the type, and that 
in many cases some of the specimens might equally well be arranged 
under the succeeding series, or, in fact, under one several rows distant, 
If we find this the case in the National Collection, which is arranged by 
experts, how can the ordinary individual ever hope to name his collec- 
tion? The true explanation of course is, that many of the so-called 
“ species’ simply represent some of the numberless seasonal forms which 
occur in Terias and Jxas, in which genera, especially in the dry-season 
forms, it is almost impossible to obtain two specimens which agree with 
one another in every minute particular, and it must be remembered that 
the “‘ species ” in these genera have in the majority of cases been differ- 
entiated on the minutest details. The result has been that when 
collections arrive at the British Museum it has been found necessary 
either to describe and name every individual or else to assign the 
specimens to that form to which they bear the closest resemblance ; 
since this latter alternative has been adopted in the majority of cases, 
the natural consequence has been that, under each “ species,” number~ 
less links to other “ species” have been arranged, one series in some 
cases running into four or five other series according to whether the 
acquisitions are incorporated on the markings of the fore- or hindwing 
or upper- or underside respectively, all of which are eminently variable, 
