450 MR. B. p. UVAROV ON THE GEOGRAPHICAL DISTRIBUTION 



the desert plains of Eastern Transcaucasia and in the dry rocky 

 districts of Persia ; we meet it again on tlie southern shore of the 

 Caspian Sea — in the district of Talysh, which is remarkable for 

 its wet subtropical climate. Some typical Balkano-Anatolian 

 fannistic elements also reach the Caucasus from the north, 

 wandering from their native home along the western and northern 

 shores of the Black Sea ^through the adjacent steppes of South 

 Russia. 



To the south of the Mediterranean subregion lies the vast 

 Eremian subregion, which includes all the deserts of North 

 Africa (Sahara, Libyan desert, Egypt), Sinai peninsula. Northern 

 Arabia, Mesopotamia, Persia-, the whole of the Aralo-Caspian 

 impression; perhaps, also, the great deserts of Chinese Turkestan 

 and Mongolia,, the Orthopteran fauna of which is but little 

 investigated as yet, belong to it. The Orthopteran fauna of the 

 Eremian subregion has many peculiarities if compared with the 

 Mediterranean, and I cannot agree with most of the zoogeo- 

 graphists* who usually unite them together. In support of my 

 opinion I give the following table : — 



Mediterranean fauna. 



Total number of species 



Number of species wbicb do not pene- 

 trate into tbe Eremian subregion ... 



Endemics 



Percentage of endemism 



Common with the Eremian subregion 



Eremian fauna. 



Total number of species 



Number of species which do not pene- 

 trate into the Mediterranean sub- 

 region 



Endemics 



Percentage of endemism 



16 



7 

 7 



56 o/o ' 100 % 

 7 



53 



46 

 42 



790/0 



9 

 9 



100 "A 



162 



130 



108 



67 Vn 



32 



137 



105 

 99 



72% 



317 



299 

 259 



82 "/o 

 18 



45 



27 



24 



53"/o 



62 



51 



41 



66"/ 



12 



31 



19 

 16 



51% 



564 



424 



69 



275 



206 

 190 



70% 



It is evident fi'om this table that the affinity between the- 

 Eremian and the Mediterranean faunas is restricted to 69 species 

 only. Out of these we must, however, not take into consider- 

 ation 48 very widely distributed species (such as Paratettix 

 tneridionalis., Acrotyht^s insuhricibs, Conocephahts niiichihcs, etc.) and 

 10 species with great power of flj'ing, which may have wandered 

 from one subregion to another in recent times ; there are, there- 

 fore, only 11 species common to the Eremian and Mediterxanean 



* W. L. Sclater was the first who recognised the difference between tlie Eremian 

 and his •' Europasian " (Boreal -t-Stepi)e + Mediterranean) subregions, but he- 

 included in it the whole of Northern Africa, the western part of which (Morocco^ 

 Algeria, and Tunis) must be united with the Mediterranean subregion. 



