452 Journal of Agricultural Research voi. xvm, no. 9 



least two, species were involved; but finally a substantial agreement has 

 been attained in the belief that the damage is the work of the single 

 species, Oscinis frit. 



In the United States the first biological observations on the species 

 were made by H. Garman {10) in Kentucky in the fall of 1889, when he 

 found the stems of young wheat infested. James Fletcher {8; 9, p. 158) 

 made the same observation at Ottawa, Canada, at about the same time, 

 and also reared the fly from larvae in stems of several grasses. Both of 

 these entomologists mention the insect as Oscinis 'variabilis Loew, a 

 species described from North America. 



In 1896 Lugger (77) reported the insect as Oscinis "variabilis Loew, 

 injuring spring wheat in Minnesota. 



In 1898 Coquillett (4) reported various rearings of what he identified 

 as Oscinis carbonaria Loew (75, 16) and O. soror Macquart. F. M. Web- 

 ster (2 j) also reported rearing the same two species from various plants 

 in 1903, his specimens having been identified by Coquillett. 



Tucker (ig) described a dark form from Colorado in 1908 as Oscinis 

 nigra, without reference to its habits. 



In 1 91 2 a monograph on the Oscinidae (or Chloropidae, as he called 

 them) of North America was published by Theodor Becker (2), of Lieg- 

 nitz, Prussia, one of the most eminent specialists on this group. His 

 work was based almost entirely on material furnished from this country 

 by Prof. A. L. Melander, of Pullman, Wash., and the writer. Becker 

 identified Oscinis frit from North America for the first time, with its 

 variety or color form O. pusilla (see Meigen 18, v. 6, p. 1^7, and p. 160 

 for Chlorops pusilla and C. frit). What had been called O. carbonaria 

 he made a synonym of 0. nitidissima, a European species described by 

 Meigen (<5, p. 388) in 1838, which he regarded as distinct from O. frit. 



Criddle (6) in 191 3 discussed the larval habits in Manitoba, believing 

 that he had detected three summer broods. 



Starting with North American material identified by Becker as Oscinis 

 frit, O. pusilla, and O. nitidissima, and with European material identi- 

 fied as O. frit by Prof. M. Bezzi and by Rev. Gabriel Strobl, the 

 writer has made a study of the North American forms. This has extended 

 to : (a) An examination of the type material of O. variabilis, 0. carbonaria, 

 0. nigra, and many other more or less related species; (b) a study of 

 reared and collected material in most of the larger collections of the 

 United States and Canada, including numerous rearings by members of 

 the Bureau of Entomology staff and nearly 16,000 specimens of the 

 species swept from vegetation in various parts of the United States and 

 Canada; (c) the rearing of more than 300 specimens from several different 

 food plants; and (d) a comparative study of the male genitalia in North 

 American and European material, including some bred from oats in 

 England. 



