952 CHARLES PauL ALEXANDER 
Antennal flagellar segments bicolorous, the basal swelling of each segment black, the 
pedicel yellow. [Proc. Acad. Nat. Sci. Phila., p. 485-487, pl. 16, fig. 10. 1915.] 
(Plate XLVI, 222, wing; Plate XLIX, 272, ninth tergite; Plate LIII, 325, eighth 
SLELNILES) si ences te, ee ete eels ee BOE ee T. cayuga Alex. 
78. Size small, wing 12 mm.; thoracic dorsum dull gray, with four brownish stripes; antennae 
unicolorous, dark brown; pleura clear light gray; sides of postnotum light yellow; 
ninth tergite (Plate aXaTIDXS 270) with two broad lobes, the notch between deep. 
(Journ. N. Y. Ent. Soc., vol. 9, fig. 99. 1901.] (Plate XLVI, 225, wing.) 
T. sulphurea Doane 
Size larger, wing 14 mm. or over; thoracic dorsum not colored as above............. 79 
79. Antennae bicolorous; thoracic dorsum dull yellow with three brown stripes, the lateral 
pair less distinct than the median one; legs long; male hypopygium with the median 
lobe of the ninth tergite (Plate XLIX, 268) entire or the bifid nature barely indi- 
eated. [T7. perlongipes Johns., Proc. Boston Soc. Nat. Hist., vol. 34, p. 131, 1909. 
T. filipes Walk., preoccupied, List Dipt. Brit. Mus., p. 65, 1848.] (Plate XLVI, 223, 
SATIS) her c 2 Mee aR Re oles eaten nee ats kena eae em a ee T. perlongipes Johns. 
Antennae unicolorous or nearly so; thorax gray, with three broad, more or less distinct, 
stripes, the median one with a delicate dark brown line; legs short; male hypopygium 
with the median lobe of the ninth tergite (Plate XLIX, 269) bifid. [Proe. Acad. 
Nat. Sci. Phila., p. 480-482, pl. 16, fig. 6. 1915.] (Plate XLVI, 224, wing; Plate 
LIII, 331, lateral aspect of male hypopygium.).................. T. kennicotti Alex. 
80. Ninth tergite (Plate LII, 309) large, the caudal margin with a small rounded notch on 
either side of a small acute median tooth; eighth sternite with broad, fleshy, lateral 
lobes directed proximad and with the ventral inner angle produced into a chitinized 
point and clothed with long yellow hairs; median area of the sternite with a prominent 
chitinized tooth on either side of the median line, broadly separated by a distance 
greater than the diameter of one tooth; size large, wing 18-20 mm.; antennae bicolorous. 
[Berl. Ent. Ztschr., vol. 7, p. 292. 1863.] (Plate XLVII, 236, wing.) 
T. umbrosa Loew 
Ninth tergite not as described; eighth sternite, if with fleshy lateral lobes (7. australis, 
T. valida, and others), without two chitinized teeth on the caudal margin of the 
sternite. 2....2 08.5.6 od sa ade ods Gunes Bale ee Hoot cn ee Oe eee 81 
81. Size large, wing over 20 mm.; male hypopygium greatly enlarged; eighth sternite with 
elongate lateral lobes and a flattened median lobe (valida group; included also in 
the section with marked wings, because the tips of the wings are usually of a darker 
gray. than the: basal part). 0.4.52 40. gus ae snoe es nt eer 82 
Size smaller, wing under 18 mm.; male hypopygium not greatly enlarged; eighth sternite 
NOt, as AbHOVE., 66 af heals cis Sh cseuels c/o e Siseecs emis als cr eee 83 
82. Ninth tergite (Plate LI, 303) with the lateral lobes more slender and pronounced; 
eighth sternite without a long brush of hairs. [Berl. Ent. Ztschr., vol. 7, p. 287. 
AS63371 (Plate 2xeU VAIL 3 7s wan.) ne) ve ses) e ees eco ee T. valida Loew 
Ninth tergite (Plate LI, 304) with the lateral lobes shorter and blunter; eighth sternite 
with a brush of long yellow hairs. [Journ. N. Y. Ent. Soc., vol. 9, p. 113. 1901.] 
T. hirsuta Doane 
83. Wing apex a little grayer than the basal cells of the wings; a brown spot at the origin 
of the sector; male hypopygium with the ninth tergite (Plate LII, 317) large, deeply 
split by a broad V-shaped notch, the lateral lobes acutely pointed. (This species is 
included also in the section with marked wings, because the tips of the wings are 
usually of a darker gray than the basal part.) ([Berl. Ent. Ztschr., vol. 7, p. 288. 
1863:|)) (Plate sa Vil 239% wings)ss5 so ee a submaculata Loew 
Wing apex unicolorous or nearly so; ninth tergite not as described.................. 84 
84, Antennae unusually elongated, if bent backward extending to the base of the fifth 
abdominal segment; ninth tergite (Plate LI, 290) with the lateral lobes subacute, 
the median lobe situated in a deep, shield-shaped depression; eighth sternite unarmed; 
antennae unicolorous; abdominal tergites bright yellow, with three distinct brownish 
