1915.] NATURAL SCIENCES OF PHILADELPinA. 489 



Male. — Length, 15 mm.; wing, 16.3 mm. 



Frontal prolongation of the head long, pale brownish yellow, with 

 a sparse whitish bloom. Palpi almost black. Antennge with the 

 three basal segments dull yellow, the remainder of the fiagellmn 

 uniformly dark bro^Aiiish. Head light gray with a subimpressed 

 dark bro^ni median vitta. 



Pronotum pale, a little darkened on either side of the middle line. 

 Mesonotal prsescutum dull gray with darker browTi vittse, the median 

 stripe divided into two by a very broad line of the ground color; 

 lateral stripes indistinct; scutellum and postnotum much clearer 

 gray. Pleura ^\dth the mesopleura clear light gray, the dorsal 

 membrane and the metapleura dull yellow. Halteres yellow, 

 passing into dark brown on the knob. Legs with the coxae and 

 trochanters dull light yellow, the former sparsely whitish poUinose; 

 femora yellow, darkened at the apex ; tibiae and metatarsus yellowish 

 brown, the segments a little darkened at the apex ; remainder of the 

 tarsi brown. Wings as in Plate XVI, fig. 12. 



Abdomen with the sides of the first two tergites bright yellowish, 

 the dorso-median line and the remaining tergites brown; segments 

 with a broad lateral and a narrow caudal pale margin; hypopygium 

 reddish; sternites brown, more yellowish laterally; segments three 

 to five with a conspicuous caudal margin of the same color. Male 

 hypopygium with the ninth tergite (see Plate XIX, fig. 51) rather 

 small, subquadrate, narrowed apically, the caudal margin with a 

 broad V-shaped notch whose edge is provided with a few chitinized 

 tubercles; a shallow dorsal median groove. Ninth pleurite incom- 

 plete, indicated beneath, situated high up on the caudal face of the 

 ninth sternite so that its inner dorsal angle about touches the ninth 

 tergite; the caudal end of the pleurite is produced caudad into a 

 flattened, subspatulate lobe (see Plate XX, fig. 67), in this suggesting 

 the condition found in T. macrolabis, though to a very much lesser 

 degree; a few scattered black hairs at the base of the sclerite on the 

 outer side, outer pleural appendage a subcylindrical fleshy lobe with 

 numerous long pale hairs; inner pleural appendage a flattened lobe 

 which lies across the genital chamber, this bearing a sharp spine 

 behind directed outward and a rounded concave lobe directed 

 dorsad, the two being portions of a high dorsal crest of the appendage; 

 cephalic arm of the appendage hidden beneath the ninth tergite. 

 Ninth sternite with a deep V-shaped notch beneath, the ventro- 

 median area pale, submembranaceous ; at the lateral end of this 

 notch and just below the pleurite is a papillose lobe directed inward 

 32 



