434 townsend: generic name musca 



Musca; its tj^pe is Musca vomitoria RD. (nee. L.) = Musca erythro- 

 cephala Meigen, which species is congeneric with vomitoria L.) 



Musca domestica L. and the species that have long been classed with 

 it under the name Musca require fresh generic reference. At least 

 three genera have been confused here, outside of Byomya and Plaxemya, 

 The type of Plaxemya is Musca vitripennis Meigen, according to well- 

 established synonymy. Musca violacea RD.^ is hereby designated as 

 the genotype of Byomya RD. (1830).^ 



Eumusca Townsend (1911) was founded on Musca corvina F. (re- 

 stricted). The new genus Promusca is here erected for Musca doriies- 

 tica L., and the new genus Viviparomusca for Musca bezzii Patton & 

 Cragg. Musca tempestiva Fallen is not typical of Promusca on ex- 

 ternal adult characters. It may form an atypical subgenus under 

 Promusca, provided reproductive and early-stage characters are 

 found to agree. Credit belongs to Portchinski*^ for suggesting, from 

 the reproductive standpoint, some thirty years ago, the distinctness 

 of the genotypes of Promusca, Eumusca, and Viviparomusca, 



Promusca Townsend, gen, nov. 



Genotype, Mwsm dofnestica Linne, Syst. Nat., ed. 10, no. 54. 1758. 



The genus is to be distinguished from all the forms hitherto confused 

 with it by the frontalia of female widening out to fill practically or nearly 

 the whole front, and the eyes of male being widely separated. There 

 are about sixty to eighty ovarioles in each ovary. The uterovagina 

 is provided anteriorly with a pair of inflatable pouches or sacs named 

 by Hewitt the accessory copulatory vesicles. Small macrotype, sub- 

 cylindrical, unpediceled, unmodified and unincubated eggs are de- 

 posited. The ovaries mature simultaneously an egg for each ovariole, 

 the whole product being normally ejected by the fly during one ovi- 

 position period. Puparium reddish-brown, 



' Ibid. 393. 



* Coquillett's designation (Type Spp. No. Amer. Dipt., 1910) of Ahisca tem- 

 pestiva Fallen as type of Byomya is invalid, since he mentions by name no origi- 

 nally included species. Were we to accept as valid a designation of an origi- 

 nally included species by number with omission of the name, the designation in 

 question would still remain invalid since it designates two of the originally 

 included species. The use of the term "supposed species" does not affect the 

 status of the case. The logical interpretation of the International Code is that 

 one, and only one, of the originally included names of species can be validly 

 designated as genotype, since this is the only course that can insure stable results. 

 Synonymy is always subject to revision. Two names supposed to be synonymous 

 may at any time prove to be distinct. 



6 Hor. Soc. Ent. Ross. 19: 210-244. 1885. 



