434 C. R. OSTEN SACKEN'S rRODROME 



Ilcih. New York, Pennsylvania, Mainland, Sonth Carolina (B. P. Mann) ; Connecticut 

 (Sonthington, in July ; W. H. Patton). I have three males and two females before me. 



This species is easily distinguished from its relations by the shape of the white abdominal 

 triangles, which are long and narrow, two or three times longer than broad, and not nearly 

 equilateral, as in the other species. The shape of the abdomen is very jieculiar, as it ap- 

 pears laterally compressed towards the tip (I did not take note, however, how the abdomen 

 appears in the living specimens). The brown clouds on the wings are less marked in this 

 species than in the three preceding ones ; sometimes they are nearly obsolete. 



The eyes of the female have two rather broad green bands on purple ground ; the lower 

 l^and at the end is bent toward the upper one ; thus the interval between them, very nar- 

 row near the front, becomes broader at the opjaosite end. 



T. catenaius ^Yalker (Massachusetts) seems to agree with this species, although the iden- 

 tification is not certain. The variety, described by Walker, Vol. V, p. 172, is a totally 

 different species. T. recedens Walker, may also be this species ; but the description does 

 not agree so well as that of T. catenatus. 



6. Tabanus abdominalis. 



Tabanus abdominalis Fabricius, Syst. Antl., p. 96, 15. (Jlicseian Hose.) 



f Tabanus ahdominalis Palisot Be.iuvois, Ins., p. 101, Tab. II, f. 4. (1809.) 



? Tabamcs abdominalis Wiedemann, Dipt. exot. I, p. 65, 6; Auss. Zw., I, p. 116, 7. 



This species and the next following are either unusually variable, or there are several 

 closely allied species, very difficult to distinguish. With the material which I have before 

 me I am unable to unravel these difficulties, and I believe that they can be solved only by 

 observations made in the localities where these species occur, observations which would 

 define the limits of the variation of each species. 



I will first describe here that species, or variety of a species, which I take to be nearest 

 to the original type of Fabricius's description ; and having done this, I will pi'oceed to de- 

 scribe the different forms which I have before me, and which may be either mei'e varieties 

 or distinct species. 



An incidental remark of Macquart's, in the introductory paragraph to the genus Tabanus 

 in the first volume of the Dipteres Exotiques (p. 116), throws more light on Fabricius's 

 T. abdominalis than the author's short descriptions. Macquart names T. ahdominalis 

 among the species with a closed first posterior cell. Where did he derive the knowledge of 

 th^character ? T. ahdominalis does not appear anywhere else in his works, nor is the char- 

 acter mentioned in Fabricius or Wiedemann. The probable and only possible explanation 

 is, that he saw in the Museum of the Jardin des Plantes, the specimen of Bosc's collection 

 originally described by Fabricius, as expressly stated in the Systema Antliatorum (Bosc's 

 collection, as well known, is incorporated in that of the Museum). If the specimens from 

 Fabricius's own collection, which Wiedemann described, or his own specimens, had had a 

 closed first posterior cell, that conscientious and careful author would certainly have men- 

 tioned this character, rather miusual among Tabanida3. Wiedemann's silence proves that 

 the specimens which he saw had the first posterior cell open ; in Palisot's figure that cell is 

 also represented as open ; and, in fact, the specimens with a closed cell are comparatively 

 rare. 



