468 MB. B. p. UVAROV ON THE GEOGRAPHICAL DISTRIBUTION 



Two of them belong to the species represented in Aclerbaidzhan 

 by other races {Duronia and Derocorys), and four are of no value, 

 their zoogeographical character being unknown [GelastorrJiinus, 

 Stenohothrus petrceus^ Flatycleis hurri, and PL decticij^ormis). 

 Thus, the difference is based on 13 species only, out of which six 

 (marked in list with an asterisk) belong to the steppe fauna and 

 seven (mai-ked with two asterisks) are Balkano-Anatolian ; they 

 all inhabit the Somkheto-Kakhetian district as well, which 

 explains their appearance in Caspian Transcaucasia through 

 recent im migration from the latter district. 



This connection with the Somkheto-Kakhetian fauna is, never- 

 theless, but of little importance, the differences between it and 

 that of Caspian Transcaucasia being too numerous. 



Summarizing these facts, we may conclude that the Ortho- 

 pteran fauna of the Caspian Transcaucasia is undoubtedly in 

 close affinity with the Aderbaidzhan fauna, being nothing more 

 than the northern vanguard of the latter, distinguished by some 

 impoverishment and by slight marks of an influence from the 

 Somkheto-Kakhetian fauna. The past history of the fauna of 

 Caspian Transcaucasia should be rather short and simple : the 

 vast plains of eastern Transcaucasia dried up after the retreat of 

 the Caspian Sea were populated by the most mobile and progressive 

 elements of the Aderbaidzhan fauna, while Balkano-Anatolian 

 and steppe forms proved mostly to be unadaptable to the rough 

 conditions of life in the newly formed deserts. 



The southern boinidary of this district, delimitating it from 

 Aderbaidzhan, is not clearly enough defined, the still continuing 

 northward migration of Eremian elements being the cause of its 

 indistinctness ; the approximate direction of this boundary is to 

 be seen above in the section dealing with the Aderbaidzhan 

 district (p. 466). 



The boundaries between the Caspian Transcaucasia and the 

 Somkheto-Kakhetian district are also mentioned above. The 

 district of Caspian Transcaucasia gi^^es a very long and narrow 

 branch noi'thwards, along the western shore of the Caspian Sea, 

 but it is still uncertain where the noithern boundarj^ is to be 

 drawn, for the deserts along this shore are as yet unexplored. 



13. The district of Caspian Ciscaucasia (C.C). 



This district is inhabited by 70 species of Orthoptera (4 M -f- 

 39 A-l-13 L + 14 G) and, as its fauna may be regarded as 

 having been thoroughly investigated, this number cannot be ex- 

 pected to increase in a marked degree after further explorations. 



A glance at the composition of this fauna enables us to conclude 

 that it belongs to the Eremian subregion. This is evident from 

 the fact of the relative abundance of Acridiodea and Gryllodea in 

 comparison with the poverty of Locustodea ; it is even still more 

 supported by the study of families : Q]]dipodid« being well 

 represented, the Decticidte also, while of the Phaneropteridse there 



