jjo. 2033. QAD-FLIES OF THE OENVS STIBASOMA—KNAB. 411 



STIBASOMA PACHYCEPHALUM Bigot. 



8tihasom.a pachycephaluvi Bigot, Mem. Soc. Zool. France, vol. 5, 1892, p. 636. 

 Tabanus chionostigma Osten Sacken, Biol. Centr. Amer., Dipt., vol. 1, 1886, 

 p. 54, pi. 1, fig. 11. 



This species is unknown to me, but from a comparison of the 

 descriptions of Bigot and of Osten Sacken, and the latter's figure, the 

 above synonymy is indicated. The figure in the Biologia shows a 

 characteristic Stihasoma, except that the thickening of the fore tibise 

 is not distinctly shown. This may be easily due to oversight by the 

 artist. The detailed figure of the antenna shows the usual process of 

 the third jomt, reaching beyond the second annulation and rounded 

 at the tip. The descnptions do not wholly agree, but I beUeve the 

 differences can be safely attributed to the individualities of the 

 authors and more particularly to the superficiality of Bigot. Bigot's 

 two specimens were from Mexico, Osten Sacken's specimen from 

 Panima, Vera Paz, Guatemala. 



STIBASOMA BICOLOR Bigot. 

 Stibasonia bicolor Bigot, M^m. Soc. Zool. France, vol. 5, 1892, p. 636. 

 Stibasoma bicolor Ricardo, Ann. Mag. Nat. Hist., ser. 7, vol. 14, 1904, pp. 361, 362 



Described from Brazil. Unknown to me. Miss Ricardo calls the 

 wings hyaline, but Bigot distinctly states that they are gray; in other 

 respects their descriptions agree. It is possible that in the specimen 

 seen by Miss Ricardo the color of the wings was poorly developed. 

 The coloration of the body appears to be much hke dyridophorum, 

 while the wings resemble those of dives. 



STIBASOMA DIVES (Walker). 



Tabanus dives Walker, List Dipt. Brit. Mus., vol. 1, 1848, p. 166. 



Stibasoma dives Ricardo, Ann. Mag. Nat. Hist., ser. 7, vol. 14, 1904, pp. 361, 362. 



Described from the Amazon. Unknown to me. Apparently 

 resembles fulvohirtus in many respects, 



STIBASOMA TRISTIS (Wiedemann). 



Tabanus tristis Wiedemann, Ausserem-op . zweifl. Ins., vol. 1, 1828, p. 164. 

 Stibasoma tristis Schiner, Reise d. Novara, Dipt., 1868, p. 94. 



Brazil. Unknown to me. 



STIBASOMA FULVOmRTUS (Wiedemann). 



Tabanus fulvohirtus Wiedemann, Aussereurop. zweifl. Ins., vol. 1, 1828, p. 155. 

 Tabanus eompactus Walker, List Dipt. Brit. Mus., vol. 5, 1854, p. 222. 

 Stibasovia fidvohirtum Schiner, Reise d. Novara Dipt., 1868, p. 94. 

 Stibasoma fulvohirtum OsTE-a Sacken, Biol. Centr. Amer., Dipt., vol. 1, 1886, 

 p. 57. 



Five females from Trinidad, sent by Prof. F. W. Urich, are before 

 me, and show remarkable variation in body coloration. Two of these, 

 hke Wiedemann's type, have the mesonotum and scutellum densely 

 clothed with bright ferruginous yellow hair; these have the first 



