«12 JOURNAL, BOMBAY NATURAL HIST. SOCIETY, Vol. XXVII. 



First of all it is evident from this table that as many as 28 out of 43 Meso- 

 potamian Acridiodea are distributed all over the countries mentioned in the 

 table; this group is composed partly of species very widely distributed generally, 

 which are of small zoogeographical interest, but not less than 12 species are of 

 peculiar interest, since their distribution is confined to the so called "desert belt" 

 of the northern hemisphere ; they are as follows : — 



Acridella robusta. 



Ochrilidia tibialis. 



Dociostaurus maroccanus. 

 „ genei. 



Mioscirtus wagneri. 



(Edipoda gratiosa. 



Helioscirtus moseri. 



Tmethis cisti. 



Chrotogonus homalodema. 



Derocorys gibbosa. 



Sphodromerus coelosyriensis. 



Thisoecetrus adspersus. 

 Some of these species are certainly to be found a little beyond the limits of 

 the deserts, as for instance both species of Dociostaurus and (Edipoda gratiosa, 

 but this fact may be easily explained by recent migration. 



The remaining 13 species which are not distributed all over the "desert belt," 

 setting aside Thisoecetrus buxtoni, which is described in this paper, and 

 j^olopus tamuhis, the occurrence of which in Mesopotamia is rather doubtful, may 

 "be divided into two distinct groups. One of these groups is composed of species 

 common to Mesopotamia and the dry desert table-lands of Persia and Asia 

 Minor, as follows: — 



* Stauroderus bicolor. 

 Dociostaurus anatolicus. 



* Pallasiella truchmana. 



* Aeolopus strepens deserticola. 



* Pyrgodera armata. 

 Oedipoda schochi. 



* Sphingonotus satrapes. 



* Leplopternis gracilis. 

 Tmethis carinatus. 



,, gibber. 



Altogether ten species, six of them (marked with an asterisk) pene- 

 trating also into the Transcaspian plains. A careful study of these species and 

 their relatives shows us most clearly that they all (except Stauroderus bicolor 

 which is dealt with later on) doubtless originated on the Iranian or Arme- 

 nian table-lands and migrated from there into the adjacent Mesopotamian and 

 Aralo-Caspian plains. As for Stauroderus bicolor which is of rather northern 

 origin, it is evident that it found its way to Mesopotamia through the 

 mountains of the Caucasus and Transcaucasia entering the plains along the 

 rivers. 



There is, lastly, only one species of Acridiodea in Mesopotamia belonging 

 to the second group which is not to be found anywhere else, while its very near 

 relatives are known from Egypt; it is described in tliis paper as Leptoscirtus 

 evansi. I think that its small size and exceedingly good protective coloration 

 account for the fact that it is not known as yet from Persia, where it ought also 

 to occur. 



Thus the Acridiodean fauna of Mesopotamia may be regarded as- a true 

 eremian fauna of the great desert belt, being under strong influence of the 

 fauna which originated on the dry table-lands of Persia and of inner Asia 

 Minor. 



