NO. 2097. FLIES OF THE GENUFi AGROMYZA—MALLOCH. 105 



Sfeciiic characters. — As indicated, all four species are similar in 

 color. All are glossy black, the abdomen being more or less dis- 

 tinctly tinged with bronze, green, or, especially at apex, with a vio- 

 laceous lustre. The wings are hyaline, but in rvparia, and especially 

 in the male of that species, they are often slightly suffused with 

 brown. The squamae are white with pale fringes. Halteres black. 



AGROMYZA RIPARIA, new species. 



Female. — Head in profile as in fig. 1 ; frons barely over one-third 

 the head width, and Ih times as long as broad; triangle glossy, long 

 and slender, reaching tlu*ee-fourths the distance to lunule; oceUar 

 bristles parallel, directed forward; orbits of almost uniform width on 

 their entire length, each equal to one-third the width of center stripe; 

 5 pairs of orbitals present, situated close to inner margin of orbits, 

 becoming sucessively weaker anteriorly, the anterior 3 pairs in- 

 curved, orbital hairs numerous though weak; arista slender, almost 

 bare, its length about H times that of width of frons anteriorly; 

 eyes without distinct pile. In front of the anterior pair of dorso- 

 centrals there are generally at least 1 pair, rarely 2, of setulae which 

 are distinctly stronger than the weak discal setulae, but which can 

 hardly be considered as dorso-centrals because of their close approx- 

 imation to the anterior pair and their inconstancy, being sometimes 

 absent on one side and present on the other in individual specimens; 

 the discal setulae are numerous, 10-12 irregular rows between the 

 dorso-centrals. Abdomen ovate ; surface with numerous short hairs, 

 those at apex and on lateral margins at base longer. Mid tibia with 

 the pair of bristles present though weak. Wings as in fig. 2. 



Length, 1.75-2 mm. 



Type-locality.— UrhsLnn, Illinois, July 4, 1914. A series of 15 speci- 

 mens taken by the writer and Mi\ C. A. Hart on vegetation in the dry 

 portions of the old channel bed of Salt Fork. Six paratypes, Algon- 

 quin, Illinois, June, July, September, and October, W. A. Nason; 

 and one, St. Joseph, Illinois, May 10, 1914, same collectors as type 

 series. 



The male agrees with the female except in having the abdomen 

 more slender, the hypopygium small and knoblike, and the wings 

 more distinctly infuscatcd. 



Food plant. — Unknown. 



Paratype.— Cat. No. 19390, U.S.N.M. 



AGROMYZA SUBVIRENS, new species. 



Female.— DiEers from riparia in head characters as follows : Frons 

 subquadrate, distinctly over one-third the head width; triangle short 

 and broad, reaching three-fourths the length of frons; orbits over 

 one-tliird as wide as central stripe; 5 pairs of bristles situated near 



