48 PROCEEDINGS OF THE NATIONAL MUSEUM vol. fiS 



KEY TO NORTH AMERICAN SPECIES OF METOPIA. 



1. Frontal vitta at level of lowest orbitals, wider than either parafrontal 4. 



Frontal vitta, at level of lowest orbitals, narrower than parafrontal 2. 



2. Anterior part of parafrontals conspicuously silvery; frontal vitta narrowed 



anteriorlj' to a line scarcely wider than lowest ocellus. 



(male) leucocephala (Rossi). 



Anterior part of parafrontals gray or leaden pollinose; anterior part of frontal 



vitta at least three times as wide as lowest ocellus 3. 



3. Pollinose area of parafrontals sharply limited posteriorly at level of lowest 



orbital bristles (male) opaca, new species. 



Pollinose area of parafrontals not sharply limited posteriorly and continuous 

 over vertex (female) leucocephala (Rossi) . 



4. Hind cross-vein strongly oblique to section of fourth vein before the bend; 



front, in profile, projects forward from the eye for a distance much less 



than horizontal diameter of eye 6. 



Hind cross vein nearly perpendicular to section of fourth vein before the 

 bend 5. 



5. Front, in profile, projects forward from the eye for distance greater than 



horizontal diameter of eye perpendicularis Van der Wulp. 



Front, in profile, projects forward from the eye for distance not more than 

 one-third horizontal diameter of eye tessellata, new species. 



6. Palpi, if present, smaller than thickened part of arista; middle tibia lacking 



bristle on outside below the middle 8. 



Palpi present and distinctly larger than thickened part of arista; middle 

 tibia with a single bristle on outside below the middle; abdomen without 

 yellow spots on its sides 7. 



7. First abdominal segment with a pair of strong marginal macrochaetae; 



middle tibia below its middle with an encircling whorl of three bristles; 



male with several long wavy hairs on outside of fore tarsus 



campestris (Fallen). 



First abdominal segment without median marginal macrochaetae; middle 



tibia lacking whorl of three bristles near its middle; male without conspicuous 



long wavy hairs on outside of fore tarsus inermis, new species. 



8. With very small distinct palpi; males with long hairs or bristles arising from 



fore tarsus 9. 



Without palpi, though sometimes with stubby rudiments; abdomen yellow 



on sides; males lacking long hairs or bristles on the fore tarsus 



sinipalpis, new species. 



9. Abdomen with pronounced yellowish spots on the sides; male with several 



long bristles on upper side of fore tarsus lateralis (Macquart). 



Abdomen usually wholly black; male with several long hairs on outside of 

 fore tarsus lateropili, new species. 



METOPIA LEUCOCEPHALA (Rossi) 



Musca leucocephala Rossi, Fauna Etrusca, vol. 2, j). 306, No. 1504, 1790, 

 Type from Europe. 



Metopia leucocephala Meigen, Illig. Mag., vol. 2, p. 280, 1803. — Coquillett, 

 U. S. Bur. Ent., Tech. Ser., No. 7, p. 127, 1897.— Bezzi and Stein, Kat. 

 Pal. Dipt., vol. 3, p. 511-512, 1907, contains a full list of numerous refer- 

 ences in European literature and 14 names of Robincau-Desvoidy assigned 

 to synonymy. — Melander and Brues, Biol. Bull., No. 5, p. 20. — Smith, 

 Ins. of New Jersey, p. 782, 1909. — Thompson, Can. Ent., vol. 43, pp. 

 313-314, 1911.— Aldrich, An. Ent. Soc. Amer., vol. 8, p. 83, 1915.— 



