OB^ ORTHOPTERA in the CAUCASUS AND WESTERN ASIA. 469 



is liere one species only — tlie very well-ilying PJianeroj^Uera 

 falcata, penetrating into this district from the neighbouring 

 district of Kubau-Terek along the valley of Kuma. 



The fauna of Caspian Ciscaucasia shows the greatest resemblance 

 to that of the district of Caspia.u Transcaucasia, the difference 

 between them being based upon the negative features of thelirst, 

 while a rather large nun)ber (46, i. e. 2 M + 1 P + 21 A + 

 17 L + S G) of Transcaucasian Ortlioptera do not range into 

 Ciscaucasia ; a careful examination of this group shows that it is 

 composed of species of distinct southern origin, except Arcyptera 

 flavicosta and Celes variabilis, which are members of the steppe 

 fauna represented in Tra.nscaucasia and Ciscaucasia as well though 

 by different geographical races. As for the positive differences 

 of the Ciscaucasian fauna, from that of Caspian Transcaucasia 

 they are 16 in number, ns follows : 



Acrida turrita turrita. (Edipoda sclioclii caucasica. 



*Chiy.sochraon dispav. **Hjalonliipis clausi. 

 *Stenobothius hsemovrboidalis, Tnietliis niuricatus. 



*Stauronotus bi'evicollis. *Saga pedo. 



* „ kraussi. *Platj'cleis moiitana. 



Arcyptera flavicosta flavicosta. Decticus ven-ucivorus scluiguvovi. 



*Epacroraia tergestina. **(>rylli!S odicus. 



Celes variabilis variabilis. **Tridactj'lus tartarus. 



Five of them are but geographical races (subspecies) of the 

 species represented in Transcaucasia as well ; one, TmetJiis 

 muricatus, is very closely related to the southern T. bilobus, and 

 is, perhaps, also but a race of the latter. The remaining group of 

 ten species is composeil of seven steppe forms (marked in above 

 list with an asterisk) and three are desert species originating from 

 the Turanian province of the Eremian subregion (tw^o a.sterisks). 

 The presence of these latter is very interesting, as it gives an 

 evidence of the affinity of the Ciscaucasian fauna to that of the 

 Kirghizian district of the Turanian pi-ovince adjacent to it 

 on the north-east. It is a very curious fact that the affinity of the 

 Ciscaucasian fauna to the Turanian province is far closer than it 

 is to the Iranian one; a comparison of the fauna of Caspian 

 the Ciscaucasia with that of the Kirghizian deserts shows us that 

 the first contains one species only which is not represented in the 

 second : this is (Edipoda schochi caucasica, an evidently new 

 intruder into the Ciscaucasian plains from the dry stony hills of 

 Transcaucasia. This leads us to the conclusion that the desert 

 plains of Caspian Ciscaucasia, quite recently left by the retreated 

 Caspian Sea, got their Orthopteran fauna mostly from the north, 

 being populated by the most progressive elements of the steppe 

 and Turanian fauna (the greater part of which are also proper to 

 the Iranian province of the same Eremian subregion). while the 

 migration from Transcaucasian deserts was prevented by some 

 unknown factors. As the eastern Ciscaucasian plains were at 

 first separated from the Kirghizian deserts by the Strait of 



