December, '14] MUIR: ORIGINAL HABITAT OF STOMOXYS 459 



Tetranychus or red spider is preyed upon by 4 species of Arthro- 

 cnodax and 1 of Mycodiplosis. It will be seen by referring to the 

 above tabulation, that Arthrocnodax displays a marked partiality for 

 the Acarina. 



The plant mites or Eriophyidae are preyed upon by 1 species of 

 Endaphis and 1 of Arthrocnodax. 



A species of gall midge, genus unknown, has been reared or was 

 supposed to have been reared from the eggs of the periodical Cicada, 

 Tibicen septeyndedm. 



It appears very probable from the above records, particularly in 

 connection with the observations of Mr. E. A. MacGregor upon Ar- 

 throcnodax Carolina, that the value of certain gall midges as natural 

 enemies has been largely overlooked. There are probably a consider- 

 able number of other species, presumably mostty undescribed, which 

 have similar habits. 



ON THE ORIGINAL HABITAT OF STOMOXYS CALCITRANS 



By F. MuiR, Taihoku, Japan 



In his interesting article on the geographical distribution of the 

 stable fly,^ Prof. C. T. Brues writes that "it is probably a native of the 

 old world, most likely of central Europe," and, near the end, "It is 

 probably native to the palsearctic region from whence it has followed 

 man in his migrations to all parts of the world," 



I am not able to follow Mr. Brues in these conclusions, and as they 

 are of some importance in economic entomology, when endeavoring 

 to discover parasites to control this pest, I would like to state my 

 reasons for differing from an authority who has given this species a 

 great deal of study. 



In judging of the native habitat of a widely distributed insect like 

 S. calcitrans, there are two points that I consider necessary to take into 

 consideration: (1) the center of activity of the genus as indicated by 

 the geographical distribution of the species of the genus; (2) the 

 number and specialization of the-natural enemies of the species under 

 consideration, and its relative abundance in the different regions. 



Turning to Brues' list of species of Stomoxys, and, if we leave out of 

 consideration calcitrans, which is world wide, nebulosa, which is 

 doubtful, and pallida, which is without given habitat, we have twenty- 

 eight species, all of which belong to the Oriental and Ethiopian regions. 

 Nine are native to India and Ceylon, and two a little to the east; 

 fourteen to the African mainland and three to neighboring islands. 



1 Jour. Econ. Ent., Vol. 6, No. G, 1913, pp. 459-477. 



