10 



OF THE TABANID^ OF THE UNITED STATES. 371 



jBoth basal cells are infuscated on their proximal half 4. 



' 1 Second basal cell hyaline ; face ferruginous in the mithlle 7. niger ilacq. 'i) ' 



Abdomen marked with more or less yellow on the sides 5. 



Abdomen altogether black G. 



Abdominal segments with narrow gray borders posteriorly ; the yellow spots on the sides of the first 



two abdominal segments small 6. sordidus n. sp. '•^ 



Abdominal segments without any gray hind borders; the yellow spots on the sides of the abdcmien 



usually large 2. excitans Walk, i.-''^ 



{Thorax with a conspicuous tuft of yellowish-ferruginous hairs on each side, in front of the 

 wings 5. celer n. sp. ^1 ^ 

 Thorax with pale yellowish hairs on the sides 7. 



fFifth posterior cell filled out with brown at the proximal end; thorax with two rather distinct whitish 



J lines anteriorly 3. mitis n. sp. ''j'^ '^ 



I Fifth posterior cell with a small hyaline spot at the jiroxiinal end; no distinct white linos on the 



L thorax 4. fugax n. sp. ^ '^^i^'"^"-'''^; 



Wliole body brownish-yellow ; abdomen with a pale-brownish design . . . .5. flavidus Wied.-^';;'3' 

 Body more or less black (or at least with black longitudinal stripes on the abdomen) .... 9. 



J Both basal cells hyaline ^ 10. 



1 First basal cell altogether, or to a considerable extent, infuscated 17. 



'The apical spot consists of a narrow brown border .along the costa, between the crossband and the 



apex; (distal half of the finst subniarginal cell, except at its extreme end, hyaline) . . . .11. 



The apical sjjot is broad, and fills out a considerable portion of the distal half of the first submar- 



ginal cell 13. 



f Crossband in the usual shape, not attenuated posteriorly 12. 

 Crossband attenuated posteriorly, the brown occupying but a small portion of the discal and fotu-th 

 posterior cells 10. delicatulus n. sp. "^ 



{A black triangle encroaches upon the yellow on each side of tlie A'S'i'iped black spot on the second 

 abdominal segment 8. aestuans v. d. Wulp. 2> ' 

 No black tiiangles on the sides of the A-shaped black spot on the second segment. 9. callidus n. sp. ST ^ 

 (The hyaline triangle, between the apical spot and the crossband, stops short at the second longitudinal 

 vein 14. 

 The hyaline triangle, etc., is prolonged beyond the second longitudin.al vein, towards the costa . .15. 

 f Second and third abdominal segments black, with yellow hind margins, expanded into triangles in the ^ 



j middle; frontal callosity reddish 11. pudicus n. sp. ^ 



' "" Second and third abdominal segments yellow, with four broad longitudinal lilack lines, which are often 



broader than the intervening yellow spaces ; frontal callosity black . . . 12. montanus u. sp. 



Abdomen dark brown, or black above, with a yellow longitudinal stripe, attenuated posteriorly, and 



two shorter and narrower stripes on each side 23. obsoletus Wied. 



I Abdomen yellow above, with two small, converging black spots on the second segment; segments 

 L three and four black and yellow 16. 



{The crossband reaches the ])osterior margin 22. fallax n. sp. ""^ "^ 

 The crossband does not quite reach the jwsterior margin, the fourth posterior cell not being quite filled 

 out with brown 21. hilaris n. sp. "^"^ 



1 The species referred to here have, in some instances, an C. monlanus, which has the largest infuscation of the first 



inconsiderable infuscation at the proximal end of the first basal cell, among all the species referred to No. 10. 



basal cell, \yWle the species referred to No. 17 have this cell C.frujidus, which has the smallest infuscation among the 



infuscated far beyond the middle. Between these alterna- species referred to No. 17. 



xW 



•S^'- 



15. 



lives, a doubt may arise in the following cases only. 



