110 DIPTERA OF NORTH AMERICA. [PART IV. 



palpi exceedingly minute, inserted at its tip. Antenna? very short, 12- 

 jointed : basal joint of the flagellum very stout ; the two apical joints only 

 are provided with long hairs. Thorax elongated, extended anteriorly into a 

 long, cylindrical neck ; mesonotum strongly projecting over the collare. 

 Tibise without spurs at the tip. Empodia indistinct or none. 



The head is proportionally small; the antennae are 12-jointed, 

 hardly longer than the head ; the first joint is very short, and 

 still shorter in the male than in the female ; the second is longer 

 and much stouter than the first, obconical ; the third is in eras- 

 sated, although less stout than the second joint ; it seems to 

 represent the coalescence of several joints ; it is more or less 

 rounded in the male, and more elongated, almost conical in the 

 female ; the remainder of the antenna is filiform ; the two apical 

 joints in the male are elongated, slender, and considerably longer 

 than the preceding joints, a difference which is not so striking in 

 the female ; the intermediate joints are cylindrical, those nearer 

 to the stout basal joint of the flagellum are sometimes very short 

 and broader than long ; the two joints of the scapus bear some 

 short bristles ; the pubescence of the flagellum is almost imper- 

 ceptible ; the two apical joints only bear some long bristles, very 

 characteristic for the genus. The front is narrow in T. magna 

 and broader in T. muliebris ; the eyes are slightly emarginate 

 on the inside, to leave room for the insertion of the antennae and 

 very closely approximated, almost contiguous, on the under side 

 of the head. The palpi, inserted at the tip of the rostrum, are 

 exceedingly minute, and their joints seem to be almost coalescent; 

 they seem to be very like those of Eiephantomyia (compare, as 

 to the structure of the palpi of this genus, Mr. Loew's figures, 

 Linn. Entom. V, Tab. II, fig. 12, 20, 21). The rostrum is 

 slender, perfectly linear, with an almost imperceptible pubescence ; 

 both species described below have it about once and a half the 

 length of the head and thorax taken together. 



The thorax is rather long, and remarkable for the great and un- 

 usual development of the mesosternum, in consequence of which 

 the fore coxae are at a considerable distance from the intermediate 

 ones ; the collare is entirely concealed under a projecting gib- 

 bosity of the mesonotum ; on the under side, the prothorax is 

 extended into a long, narrow, cylindrical neck, to which the head 

 is fastened ; the metathorax is also much developed, rather long 

 and horizontal. The feet are long and slender ; their pubescence 



