40 



Americans). These are northern forms, abundantly represented in 

 Sweden, and as in the northern United States we can expect a few, 

 but not many additions in them, the poverty of the fauna becomes 

 clearly apparent. We may conclude by saying in general that North 

 America, as far as our figures go, seems poorer in Syrpliidae than 

 middle and northern Europe. Our data, it is true, especially refer 

 to the northern regions of this continent. If the Southern States 

 were better explored, and if, as an equivalent for the Mediterranean 

 fauna of Europe, Mexico and the West Indies were thrown in, with 

 their numerous species of Eristalis and Voludella the balance would 

 be, of course, somewhat restored in favor of America. Still, this 

 relative poverty of the northern regions of North America in 

 SyrjjJii'dae is worth noticing, especially if Ave recall the fact that in 

 the Tabanidae, Tipulidae, Dolichopodidae and other families, these 

 regions fully equal, and often surpass Europe in tlae number of 

 species, 



3. The genera peculiar to America are as follows : Mesograpta, 

 closely allied to Syrplms, is represented by six species in the United 

 States and by many more in the tropics. To Mixtemyia, hitherto 

 represented by a single species, not rare in the northern States of 

 the Union, I have added in the appendix a second species from 

 Mexico. The genera Allograpta and Teiiclwcnemis which I propose, 

 will also probably be increased by the addition of southern species ; 

 Pteropitila, Lepidorayia and Pterallastes belong in the same cate- 

 gory. Ceratophyia, Mixogaster, Somula and PoJydonta close the 

 list of genera peculiar to America. Except Mesograpta, all these 

 genera are hitherto represented by very few species, most of them 

 by a single one. 



4. Of the one hundred and sixty Syrpliidae from the United 

 States, north of Mexico and exclusive of California, which are 

 described and actually identified in our collections, about twenty- 

 five are species common to Europe and North America. 



