OF THE TABANIDiE OF THE UNITED STATES. 429 



rLateral abdominal spots yellowish; front narrow; upper angle of tliird antonnal joint prominent; 



ow J femora usually dark 26. fulvulus Wied. 



I Lateral abdominal spots whitish; front bi'oad ; upper angle of third antennal j(jint very shallow; 



L femora reddish 27. sagax n. sp. 



A distinct frontal callosity present 29. 



No frontal callosity 38. mexicanus Linn. 



nn J Both abdomen and palpi black 30. 



' I Either abdomen or palpi not black 35. 



- r Prevailing color of thorax and wings not black 31. 



I I'revailing color of the whole body black 33, 



("Thorax dark brown above; wings subhyaliiie, with brown clouds on crossveins. 28. nigrescens Palisot. 

 °^- 1 Thorax densely clothed with white pollen or down 32. 



09 r Front tibife white at base 29. punctifer n. sp. 



I Front tibipe not white at base 30. Stygius Say. 



„„ r Front unusually broad, callosity transverse 31. atratus Fab. 



' 1 Front not unusually broad, callosity not transverse 34. 



„^ r Narrow portion of the third antennal joint not remarkably elongate . . 32. Wiedemanni n. sp. 



' 1 Narrow i)ortion, etc., remarkably elongate . 33. lugubris Macq. 



„^ r Abdomen broadly red on the sides, black in the middle -36. 



' 1 Abdomen black or brown 37. 



r Legs and palpi pale reddish 34. rufus Palisot. 



■ I Legs and palpi dark 35. Megerlei Wied. 



„„ r Wings hyaline, with a dark brown costal cell 36. americanus Forster. 



I Wings uniformly brownish yellow 37. giganteus DeGeer. 



Abdomen without white spots ; front (?) without callosity 39. 



Abdomen with three rows of white spots ; frontal callosity distinct 40. 



r Pectus and pleurae yellowish 39. bicolor Wied. 



1 Pectus and pleurie gray 40. fulvescens Walk. 



fGray; third antennal joint not very deeply excised ^ 41. Rein'wardtii Wied. 



40. 1 Light chocolate brown ; third antennal joint deeply excised, almost crescent-shajsed 42. cerastes n. sp. 



f Prevailing color of the body pure black or brown 42. 



41. -( Prevailing color of the body grayish black or blackish gray ; sides of the abdomen often reddish (large 



I group of northern species) 45. 



._ J Abdomen with conspicuous yellow crossbands 43. 



" [Abdomen without yellow crossbands 44. 



f Ante-alar tubercle black; the yellow abdominal crossbands consist of a narrow fringe of pale yellow 



-„ J hair 43. flavipes Wied. 



I Ante-alar tubercle reddish; yellow crossbands broad, formed by yellow hair on a broad border of yel- 



l lowish pollen 44. zonalis Kirby. 



f Three first abdominal segments bright orange red, tlie rest black 45. cinctus Fabr. 



44. -j Abdomen with a white triangle on each of the segments two, three, four ; body of male brownish 



[. black; of female grayish black (dark slate color) 46. trispilus Wied. 



'Abdomen with a conspicuous row of white triangles in the middle of the segments, but without lateral 



white spots (see No. 46, trisjyilus Wied., female). 

 Abdomen rufous on the sides, this color leaving only a narrow black stripe of the first three or four 



segments 46. 



I Abdomen on each side with a conspicuous row of white or whitish spots ; the rufous color less appar- 

 [ ent, or not existing 48. 



' If the species to be determined is from the for west (Col- (No. 54), the ocellar tubercle of which is often not denuded, 

 orado Mountains, etc.), compare at this place T. rhombicus and might be supposed wanting. 



MEMOIES P-'ST. EOC NAT. HIST. YOL. H. lOS 



38. 

 39. 



45, 



