46 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 68 



Ophelia Robineau-Desvoidy, Myod., p. 120, 1830. Preoccupied 1817 in 

 Vermes. The genotype according to Bezzi and Stein, Kat. Pal. Dipt., 

 vol. 3, p. 510, equals cam-peslris in Metopia. — Townsend, Ins. Ins. Menst., 

 vol. 4, p. 8 gracilis Robineau-Desvoidy designated as type. 



Araba Robineau-Desvoidy, Myod., p. 127, 1830; Dipt, des Environs de 

 Paris, vol. 2, p. 88, 1863. This name modified by the author to Arabella, 

 for sake of euphony. Genotype designated by Desvoidy in 1863, Tachnia 

 argyrocephala Mcigen, which equals leucocephala Rossi, the genotype of 

 Metopia. 



Anicia Robineau-Desvoidy, Dipt. Envr. Paris, vol. 2, p. 99, 1863. Geno- 

 type, sabulosa which according to Bezzi and Stein, Kat. Pal. Dipt., vol. 3, 

 p. 510, belongs in the genus Metopia. 



Arabella Robineau-Desvoidy, Dipt. Envr. Paris, vol. 2, p. 88, 1863. Geno- 

 type, Tachina argyrocephala Meigen considered by some European workers 

 as synonymous with leucocephala and by others as a very nearly related 

 species in the genus Metopia. 



Argyrella Robineau-Desvoidy, Dipt. Envr. Paris, vol. 2, p. 87, 1863. 

 Genotype, dissimilis which according to Bezzi and Stein, Kat. Pal. Dipt., 

 vol. 3, p. 512, equals leucocephala in Metopia. 



Argyria Robineau-Desvoidy, Dipt. Envr. Paris, vol. 2, p. 82, 1863. Pre- 

 occuppied by Hubner in Lepidoptera, 1816. Genotype leucocephala of 

 Rossi which, however, is type of Metopia. 



Parametopia Townsend, Proc. U. S. Nat. Mus., vol. 49, p. 619, 1914. 

 Genotype, rnorrisoni which equals lateralis Macquart and is congeneric 

 with leucocephala. In this synonomy, I have followed Bezzi and Stein, 

 adding to their list Townsend's Parametopia after comparison of genotypes. 



The known North American species of the genus Metopia possess 

 the following characters. Width of front is with some species greater 

 in the male, in others in the female. There is a single frontal row on 

 each side of the vitta, extending as far as, or slightly below, base of 

 second antennal joint, suddenly divergent below; lunule conspicuous, 

 nearly half as long as wide; small proclinate ocellar bristles present; 

 orbital bristles in both sexes, four on each side, of which the lowest 

 is proclinate, the uppermost reclinate, and the intermediate two decus- 

 sate; facial ridges divergent, with small bristly hairs not extending 

 above the lowest fourth; vibrissae nearly or quite level with oral 

 margin; antennae extending nearly to vibrissae; penultimate joint of 

 arista at most slightly longer than broad; parafacials with a row of 

 strong macrochaetae bordering the facial ridges, becoming progres- 

 sively larger as they approach the vibrissae; in profile, head length 

 at vibrissae much less than at base of antennae, epistoma not visible, 

 head with a pronounced conical contour; bucca and back of head 

 with black bristly hairs, no pale hairs on the sides and back of oral 

 cavity; facets of eye at extreme front but slightly larger than those 

 at side of head; proboscis rarely one-half head height, very short and 

 stout, with large fleshy labella; palpi moderate to very small in size 

 or entirely lacking. Thorax with two sternopleural bristles and tliree 

 strong postsutural dorsocentrals; scutellum with three pairs of strong 

 marginal bristles. Pollen of abdomen usually interrupted by one to 



