IN SEARCH OF RUSSIAN BUTTERFLIES. O71 
mediate forms occur, and it is beyond reasonable doubt that these are 
hybrids. It is known that a number of Asiatic species produce these 
intermediate forms or natural hybrids; and there are certain species 
occurring in Hurope which there is good reason to suppose hybridize 
also; for instance, in the only locality in which the two Arctic 
species C. hecla and C. werdandi are known to frequent the same 
ground, an intermediate form, ab. christiienssoni, Lampa, has been 
taken, apparently in numbers, jndging from the series of it that we 
have in the National Collection. At Sarepta intermediate forms 
between C. erate and C. hyale and between C. erate and C. edusa are 
well known, and there are examples of both these forms in the 
National Collection. The first-named cross is known as C. hyale var. 
sareptensis, Stgr., and the second C. erate var. chrysodona, Boisd. 
Seitz has muddled the nomenclature of the former hybrid in his 
work; he first, in the description of the different forms of C. hyale, 
calls it var. sareptensis, and then, amongst the forms of C. erate, 
gives it the new name of var. diana. Obviously, hybrid forms 
between two species cannot have more than one name and, therefore, 
Staudinger’s hyale var. sareptensis must stand. Seitz figures both 
hybrids. It seems probable that the vigorous male of C. erate is 
responsible for these abnormal pairings, which in the case of erate x 
hyale produced offspring at Sarepta more numerous than the typical 
C. hyale. The hybrid erate x edusa was not abundant; I only saw 
some half dozen of it in all: these were very constant and without 
variation ; but of the erate x hyale hybrid there is every form, from 
almost typical C. erate to almost typical C. hyale. One wonders if 
these hybrids are not fertile enter se, or with one or both of the 
parent species. One possible reason why the Colias species hybridize 
freely is that the genitalia of many of them are so similar there 
seems no physical obstacle to their doing so. The similarity in 
these organs prevents them being used as factors to identify the 
various hybrids. 
Gonepteryx rhamni.—Hibernated specimens were seen at Ialta 
and Sarepta, and in the latter locality freshly emerged examples 
were frequent from June 16th; they are rather smaller than those I 
have from Britain and Central Europe; the males are a little more 
richly yellow, and the females rather whiter. 
Thecla w-album.— Common in clearings in the ‘“ Tschapurnik 
Wald” from June 16th; they were very partial to the flowers of 
Gypsophila paniculata and other plants. 
7’. tlicis.—In the same locality as the last, apparently not abun- 
dant; the only example I brought away is a typical female. First 
seen on June 16th. 
T. spint.—Abundant and generally distributed from June 12th 
onwards; they were the type form without any approach to ab. 
lynceus. 
T’. prunt.—l saw three or four fresh specimens in the “Tscha- 
purnik Wald” on May 22nd, flying over blackthorn bushes, but did 
not come across it afterwards; the only one captured, a male, does 
not differ from those I have from Central Europe. 
T. acaciae.—First seen on June 4th; not uncommon, and 
generally distributed amongst blackthorn. The only difference I can 
