OF THE TABANID^ OF THE UNITED STATES. 375 



dense on the sides and towards the apex ; on the second and third segments this pubes- 

 cence forms faint triangles. Legs black, root of the four posterior tarsi brownish. Pattern 

 of the wings as in C. excitans, except that the brown coloring is somewhat less dark, and 

 that the brown in the two basal cells reaches a little farther, so that the hyaline space be- 

 tween this brown and that of the crossl^and is a little narrower, especially in the second 

 cell. An indistinct whitish halo along the distal margin of the crossband. 



Hab. British Possessions in N. America from Canada (W. Couper), to MacKenzie and 

 Yukon Rivers (R. Kennicott) ; Lake Superior. Nine females. 



This species is not unlike C. excitans, but is easily distinguished by the altogether black 

 coloring of the abdomen, the two gray stripes on the thorax, which are much more distinct 

 than the corresponding yellowish lines in that species, the above indicated slight difference 

 in the coloring of the wings, etc. The brown of the picture, in most specimens, seems to 

 be a httle less dark than in C. excitans. The resemblance of G. mitis to C. celer will l^e 

 discussed under the head of the latter species. 



The identity of Mr. Walker's G.provocans with the present species seems probable. The 

 statement that the facial callosities are larger than those of C excitans agrees with this spe- 

 cies better than with C. celer ; the "tuft of pale yellow hairs . . . at the base of the 

 wings", describes the pubescence of C. mitis, rather than the ferruginous pubescence of C. 

 celer ; but the statement that the crossband approaches nearer the hind border than that of 

 C. excitans, renders the identification doubtful. 



Macquart's description of C. ater agrees with the present species, except in size. As he 

 compares G. ater to C. niger and at the same time makes it half a line smaller, the identi- 

 fication with C. mitis becomes impossible. 



4. Chrysops fugax n. sp. 



? Chrysops carhonarius Walker, List, etc., I, p. 203 {exparte). 

 ? Chrysops ater Macquart, Dipt. Exot. 4° Suppl., p. 40. 



?. Like C. mitis, but smaller; whitish lines of the thorax imperceptible; gray triano-les on abdomen 

 almost imperceptible ; a small hyaline spot at the proximal end of the fifth posterior cell. 

 Length, 8-9 mm. 



I should hesitate to separate this from the preceding species, if it were not for the con- 

 stancy of the characters just given. I have fourteen female specimens before me ; from 

 Norway, Me. (S. I. Smith), Gorham, N. H. (Austin), Canada (W. Couper), divide between 

 Idaho and Montana (C. Thomas), Yukon River (Kennicott). All agree in having the fifth 

 posterior cell hyaline at the proximal end, and not filled out with a brownish tinge; this hy- 

 aline spot coalesces with the hyaline space in the second basal cell. All such specuneus are 

 considerably smaller than the average-sized specimens of C. mitis and the best preserved 

 among them show but a vestige of the whitish lines on the anterior part of the thorax, which 

 are comparatively distinct in the other species. The dorsal triangles on the abdomen also, 

 are hardly perceptible or not visible at all. Li size and general appearance this species is 

 not unlike C. nlrjer, and I suspect that Mr. Walker's O. carhonarius is a mixture of the 

 present species with C. niger Macq. His Var. ^ would, in this case, especially refer to C. 

 niger. All the statements, which do not agree with C.fugax (as that the crossband "ex- 



