ON THE TERMINOLOGY OF DIPTERA. XIX 



logical expressions, since it is not so much the nature of the re- 

 ceived terms as the consent in their application which we must 

 aim at. I therefore think it most advisable to retain such names 

 for the denomination of the wing-cells, as are already in general 

 use. But in adopting these names I cannot but mention that 

 many of them do not seem to be well chosen, and that I accept 

 them only with the intention of bringing about a terminology 

 generally agreed upon. 



I shall, therefore, call the cells belonging to the first section of 

 the wing the costal cells (celhdse costales}, those of the second the 

 marginal cells (celhdse marginales), and those of the third the sub- 

 marginal cells (cellules submarginales). The latter are of the greatest 

 importance for characterizing families and genera, as well as for 

 the distinction of species. When the second and third longitudi- 

 nal veins are simple, and the third anterior section is consequently 

 undivided, there exists only one submarginal cell; but when the 

 third longitudinal vein has a branch running to the border of the 

 wing, we count two such cells, an anterior and a posterior one ; 

 when the anterior branch of the third longitudinal vein is also 

 connected with the second longitudinal vein by a transverse vein, 

 the number of submarginal cells amounts to three, among which 

 that, formed by the inner part of the anterior submarginal cell, is 

 called the interior submarginal cell ; when the anterior branch of 

 the third longitudinal cell assumes the form of a transverse vein 

 running to the second longitudinal vein, only an interior and an 

 exterior submarginal cell are distinguished. 



Among the existing names, none is. well applicable as a common 

 denomination either to the cells belonging to the middle of the 

 wing or to those of each of the two first sections of the posterior 

 part of the wing ; I am compelled, therefore, though not without 

 reluctance, to give up the application of such names. Among the 

 cells of the portion just mentioned, there are three that have gene- 

 rally been too little noticed in the description of the neuration of 

 the wing. Their different forms give very good characters, the 

 more so as, on the whole, the differences, which the neuration 

 shows in the neighborhood of the base and costal border, have 

 always a higher systematic value than those occurring near the tip 

 or the posterior border of the wing. Those three cells are placed 

 nearest to the base of the wing ; the first of them belongs to the 

 middle of the wing, and reaches as far as the small transverse 



