17 



the males and females are similar, for the distinct grayish markings 

 on the abdomen and the subhyaline of the wings in the southern speci- 

 mens of the female become obsolete in the more northern specimens. 

 The common green-head, Tahanus nigrovitta Macq., of the Atlantic 

 coast from Maine to Florida varies greatly in size in different localities. 

 When attaining a length of 12 to 14 mm. it is the T. conterminus 

 Walker. Tahanus atratus when breeding in the saline marshes, 

 assumes a form known as nantuckcnsis Hine. 



Since the following generic names are being used, it might be well 

 to call attention to the fact that they are both preoccupied. 



Pandora Haliday, 1833, was used by Hendel (Wiener Ent. Zeit,, 

 1910) and adopted by Melander (Wash. Agric. Exp. Sta., Bull. 143, 

 1917) in place of Saltella Robineau-Desvoidy, 1830, although the latter 

 has been used prior to 1910 without question. It is preoccupied in 

 Mollusca by Pandora Bruguiere, 1792. 



Melina Robineau-Desvoidy, 1830 (Myodaires, p. 695) is used by 

 both Cresson (Trans. Amer. Ent. Soc, 1920, vol. 46, p. 41) and Mel- 

 ander (Ann. Ent. Soc. Amer., 1920, vol. 13, p. 313) for the Sciomyza 

 of authors, not Fallen. A second name by Robineau-Desvoidy, 

 Pherbellia (Myodaires, 1830, p. 695) will have to be substituted as 

 Melina was used in Mollusca by Retzius in 1788. 



