ART. 17. FLIES OF THE GENUS TACHYTEECHUS GREENE. 7 



4. TACHYTRECHUS FLORIDENSIS Aldrich. 

 Fig. 4. 

 Tachytrechits florUJcnsis Ai^drich, Trans. Amer. Ent. Soc, 1S96, vol. 23, 

 p. 82. 

 Male. — Face silvery white, nearly twice as wide on the lower part 

 as it is immediately below the antennae. Front greenish, heavily 

 coated with a whitish dust. Antennae black, first and second joint 

 a little elongated; third joint rounded. Arista black, slightly longer 

 than the antennae. Orbital cilia mostly white, just a few black bris- 

 tles above. Thorax green, heavily coated with a white dust around 

 the sides, more of a brownish in the center. In some lights the green 

 ground color is quite visible. Just above the root of the wing is a 

 dark brown spot. Scutellum green with a coating of golden brown 

 dust. Abdomen metallic green heavily coated with a white dust; 

 down the center of the dorsum and along the apical edge of each seg- 

 ment more shining, near the apical edge of each segment is a trans- 

 verse row of large black bristles. Hypopygium large, first joint 

 small, next joint large and globular, covered with a whitish dust and 

 fine black hairs, lower edges shiny reddish-black; lamellae nearly 

 black, somewhat triangular ; the outer lower edge rounded and with 

 long black hairs. All the coxae dark with a silvery dust. Front and 

 hind femora on their basal two-thirds and the middle pair on slightly 

 more than their basal half, greenish covered with a silvery dust; 

 tibiae reddish-yellow with brownish tips and all tarsi dark brown. 

 Wings hyaline, slender, rounded at tip with a large, round blackish 

 brown spot at apex ; this spot extends narrowl}?^ before the third vein 

 and is separated from the posterior edge of the wing by a very narrow 

 hyaline margin. Posterior cross vein straight. Halteres pale yellow. 

 Tegulae pale yellow with long black cilia. 



Female. — Very much like the male except as follows : Face only 

 ilightly wider. Antennae a little shorter. Wings not quite so nar- 

 row and without the apical spot. On the outside of the fore tibiae 

 there are one or two small black bristles in a third series. 



Length 5 mm. 



Type locality, — Florida, F. H. Snow, collector. 



Cotype, male and female.— Cat. No. 24140, U.S.N.M, Deposited 

 by J. M. Aldrich in United States National Museum collection. 

 Originally described from two males and two females, labeled " Fla." 



One specimen, a male, from Biscay ne Bay, Florida, Mrs. Slosson, 

 collector. In United States National Museum. 



5. TACHYTRECHUS VOUTAMS Melander, 



Fig. 3. 



Tachytrechus voUtans Melander, Can. Ent.. 1900. vol. 32, p. 143, fig. S. 



Face broad, dull, pale yellow (in certain lights pale golden), 



wider below, narrower above (just below the antennae). Front dull. 



