954 Charles Paul Alexander 



basal segments light yellow, the remainder of the organ more or less distinctly bicolorous; 

 abdomen dull vellow, the tergites with a conspicuous dark brown stripe; wing 12 mm. 

 [Proc. Acad. Nat. Sci. Phila., p. 475-476, pi. 16, fig. 5. 1915.] (Plate XLVIII. 253, 



wing; Plate LIV, 346, lateral aspect of male hypopygium.) T. mainensis Alex. 



Coloration not as above, the thoracic stripes not dark brown; hypopygium not as 

 above 91 



91. Nasus short; cell 1st Mi of wings very small and pentagonal; male hypopygium with 



the ninth tergite usually tumid, unarmed or provided with horns; in species in which 

 the tergite is not conspicuously swollen and tumid (T. parshleyi), the cell 1st Mi is 

 small and pentagonal, as above; in species in which the cell \st M2 is longer 



{T. jofmsoinana), the ninth tergite is tumid tho unarmed {bicornis group) 92 



Nasus usually longer; cell 1st M2 of wings not small and pentagonal; male hypopygium 

 with the ninth tergite not tumid (travslucida group) 96 



92. Ninth tergite (Plate LII, 321) not tumid; eighth sternite very long, sheathing the ninth 



sternite beneath, the tip with two chitinized points on either side. [Proc. Acad. 

 Nat. Sci. Phila., p. 510-512, pi. 17, fig. 23. 1915.] (Plate LV, 354, lateral aspect 



of male hypopygium.) T. parshleyi Alex. 



Ninth tergite tumid; eighth sternite shorter, not closely applied to ninth sternite for 

 the entire length of the latter, the apex without chitinized points 93 



93. Ninth tergite (Plate LII, 320) with four lobes or horns. [Journ. N. Y. Ent. Soc, vol. 9, 



p. 112-113. 1901.] (Plate XLVI, 231, wing; Plate LV, 353, lateral aspect of male 



hypopygium.) T. megaura Doane 



Ninth tergite with two horns or without horns 94 



94. No horns on the tergite (Plate LIT, 318). [Proc. Acad. Nat. Sci. Phila., p. 505-506, 



pi. 17, fig. 20. 1915.] (Plate LV, 351, lateral aspect of male hypopygium.) 



T. johnsoniana Alex. 

 Horns on the tergite 95 



95. Horns on tergite (Plate LII. 319) directed upward. [16th Kept. State Ent. 111., p. 78, pi. 6, 



fig. 4. 1891.] (Plate XLVI, 230, wing; Plate LV, 350, lateral aspect of male hypo- 

 pygium.) T. bicornis Forbes 



Horns on tergite directed caudad or slightly ventrad. [Proc. Acad. Nat. Sci. Phila., 

 p. 507-508, pi. 17, fig. 21. 1915.] (Plate LV, 352, lateral aspect of male hypopygium.) 



T. viorrisoni Alex. 



96. Caudal margin of ninth tergite (Plate LII, 315) with three prominent lobes, the median 



lobe acute; antennae bicolorous; body coloration light yellow, the thoracic stripes 

 reddish brown; abdomen with a series of about four conspicuous, rounded, brown 

 spots along the sides; wing 13.5 mm. Southern species. [Proc. Acad. Nat. Sci. Phila., 



p. 487-488, pi. 16, fig. 11. 1915.] (Plate XLVII, 240, wing.) T. triton Alex. 



Caudal margin of ninth tergite not trifid 97 



97. Caudal margin of ninth tergite (Plate LII, 316) deeply notched, the lateral lobes pro- 



duced into long, slightly curved horns; outer pleural lobe a conspicuous curved hook; 

 antennae bicolorous; body coloration yellowish, the thoracic stripes very indistinct; 

 wings vellowish; wing 17.2 mm. [Proc. Acad. Nat. Sci. Phila., p. 493-495, pi. 16, 

 fig. 15.' 1915.] (Plate XLVII, 241, wing; Plate LIII, 328, eighth sternite; Plate 



LV, 349, lateral aspect of male hypopygium.) T. tuscarora Alex. 



Male hypopygium not as above 98 



98. Lateral lobes of ninth tergite (Plate LII, 310) broad, squarely truncated; antennae more 



or less distinctly bicoloroup; coloration brownish yellow; wing 18 mm. [Proc. Acad. 

 Nat. Sci. Phila., p. 490-492, pi. 16, fig. 13. 1915.] (Plate XLVII, 242, wing.) 



T. mingwe Alex. 



Lateral lobes of ninth tergite not squarely truncated, more or less pointed or 



rounded 99 



99. Lateral lobes of ninth tergite pointed 100 



Lateral lobes of ninth tergite rounded 102 



