NORTH AMERICAN DIPTERA. 



der, and called the auxiliary vein, is the subcostal cell ; 

 between the auxiliary vein and the costal border itself is 

 the costal cell. 



Finally, near the root of the wing, a short, but very 

 constant cross-vein connecting the auxiliary vein with 

 the costa is the humeral cross-vein (a). 



The above is the nomenclature of the wing now having 

 almost universal vogue among descriptive entomologists, 

 a s}^stem which, with minor modifications, has been used 

 almost from the beginning of descriptive dipterology. It 

 has no especial superiority over other systems to com- 

 mend it, nor has it any striking disadvantages to con- 



Fig. 13. Wing of Pangonia. Schiner's nomenclature. 



i, costal cell; 2, mediastinal cell; 3, subcostal cell; 4, 5, cubital cells; 

 6, 7, 8, 9, n, first -fifth posterior cells; 12, discoidal cell; 13, 14, 15, 

 first-third basal cells; 16, axillary cell. 



demn it; and long usage has apparently fixed it. An- 

 other system in vogue at the present time among a few 

 dipterological authorities is that used by Schiner in his 

 later writings, and, which, could it displace the older 

 system, would have much to commend it. It will be 

 readily understood by the comparison of the tw r o figures 

 given. The only confusion it makes with the older 

 system is in the use of mediastinal cell for subcostal and 

 subcostal for marginal, and this confusion is actually 

 apparent in the writings of some authors, of whom Ver- 

 rall is an example. 



