242 Annals Entomological Society of America [Vol. VI, 



vulgaris Fall, with its five and one-half pages of synonymy in 

 the '"Katalog der Palaarctischen Diptera" is sufficient in itself 

 to establish the desirability of studies in variation. 



The present study is concerned with three species of the 

 genus Lucilia i. e. sericata Meig. sylvarum Hough and ccBsar 

 Linn. The method adopted was to breed from isolated egg 

 masses series of adults, examine and record certain selected 

 characters for each fly from each egg mass, tabulate these charac- 

 ters, make synopses of these tables, and finally to draw up from 

 these s^mopses resumes or extended definitions for each species. 



Owing to lack of space only these final resumes appear in 

 this paper. It was the intention of the writer at the outset 

 to keep exact records of at least one hundred examples of each 

 species encountered. This intention was however only realized 

 in the case of L. sericata in which case several hundred adults 

 were reared. The riumber of specimens of each species reared 

 and examined is as follows: 



L. sericata, Meig., 158 consisting of 57 9 9 and 101 d' (J". 

 L. sylvarum, Hough, 27, consisting of 25 9 9 and 2 cf'cf. 

 L. CEesar, Linn., 3, consisting of 1 9 and 2 cf cf . 



In addition to these bred specimens ten collected specimens 

 of L. sylvarum and thirty-one L. caesar were also examined, 

 the results being included in the following resumes. This 

 makes the total assemblage of flies for each species: L. sericata, 

 158; L. sylvarum, 37; L. caesar, 34. 



The characters selected for examination were as follows : 



Dorsocentral bristles. 



Postracostichal bristles. 



Humeral bristles. 



Sternopleural bristles. 



Ocellar bristles. 



Width of front. 



Colour of palpi. 



Colour of first abdominal segment. 



Marginal bristles of second abdominal segment. 



Colour of tegulas. 



Width of apex of first posterior cell compared with the length of the anterior 



cross-vein. 

 Presence or absence of appendage at bend of vein four. 



These particular characters were chosen for two reasons 

 (a) to find if possible new taxonomic characters for the separ- 

 ation of the species; (b) on account of the fact that they include 

 all the new characters employed by Mr. C. H. T. Townsend* 

 in the erection of ten supposedly distinct species. 



* Taxonomy of Muscoidean Flies. Smithsonian Misc. Col., Vol. 41, No. 1803. 



