IN SEARCH OF RUSSIAN BUTTERFLIES. 271 



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 fot-ms or natural hybrids ; and there are certain species 

 occurring in Europe 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. christuenssoni, Lampa, has been 

 taken, apparently in numbers, judging from the series of it that we 

 have in the National Collection. At Sarepta intermediate forms 

 between C. erate and C. hyale and between G. crate 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 G. hyale, 

 calls it var. sareptensis, and then, amongst the forms of G. 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 G. erate is 

 responsible for these abnormal pairings, which in the case of erate x 

 hyale produced offspring at Sarepta more numerous than the typical 

 G. 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 G. erate to almost typical G. hyale. One wonders if 

 these hybrids are not fertile inter se, or with one or both of the 

 parent species. One possible reason why the Golias 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 lalta 

 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 pianiculata and other plants. 



T. ilicis. — 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. spini. — Abundant and generally distributed from June 12th 

 onwards ; they were the type form without any approach to ab. 

 lynceus. 



T. pruni. — I 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 



