42 
14. 
15. 
16. 
17. 
18. 
19. 
20. 
22. 
23. 
24. 
20. 
DIPTERA. 
Head not swollen; frontal bristles arranged in one or more 
rows on each side of the frontal band . 
Facial ridges with a row of bristles (eyes pilose, at least in 
the male) . toe ee woe ee . . 
Facial ridges without, or, at most, with some scattered, bristles . 
Frontal bristles on each side in two or three rows; eyes bare 
Frontal bristles on each side in a single row; eyes pilose . 
Eyes hairy * 
Eyes bare Loe ee Loe 
Metallic green species; antennz rather short 
Grey or black, seldom fulvous or partly fulvous species (in a 
few species of the genus Mystacella, the abdomen with a 
tendency to metallic coloration) ; antennz rather long . 
Vibrissz inserted at some distance above the oral margin . 
Vibrisse inserted just at the oral margin . . 
Curvation of the fourth vein with a rectangle ; apical cross- 
vein usually concave ; abdomen ovate . 
Curvation of the fourth vein with a blunt angle; apical cross- 
vein straight ; abdomen conical . . . 
Facial ridges without bristles (sometimes with a few bristles 
immediately above the vibrissz) 
Facial ridges with a row of bristles 
. Antenne very short . 
Antenne elongate, often nearly as long as the face . . 
Cheeks as broad as the rongituinar diameter of the eyes ; 
macrochete as usual . . Se 
Cheeks narrow, the eyes descending to near the inferior part 
of the head ; macrocheete very short and weak 
Facial ridges without bristles (sometimes with a few bristles 
placed at a considerable distance from each other, or some 
immediately above the vibrissz) . 
Facial ridges with a row of bristles extending up half the face 
Vibrissze inserted at some distance above the oral margin 
Vibrissz inserted quite at the oral margin . . 
Second joint of the antenne rather elongate, the third, at 
most, twice as long as the second; some veins of the wings 
bristly ; fourth vein prolonged at its point of curvature; the 
apical and especially the posterior cross-vein very oblique . 
Second joint of the antenne very short, the third more than 
14. 
Distichona, v. d. Wulp. Lf UY : 
15. _ 
Cnephalia, Rond. US 
Nemorea, Rob.-Desv. 1’ 
17. 
21. 
Gymnocheta, Rob.-Desv. 
18. 
19. 
20. 
Mystacella, v. d. Wulp. 3] 
Meigenia, Rob.-Desv.4 8 
Ezxorista, Meig. 60 
Phorocera, Meig. ‘75~ 
22. 
23. 
Tria, Meig. 87 
Miltogramma, Meig. as 
24. 
26. 
 Grachiycona, Rond. Jo 
25. 
Plagia, Meig. /0/ 
* The genus Plagia is ranged here under No. 21; most of its species have the eyes bare, but a few of them 
(including one belonging to the Central-American fauna) have the eyes thinly pilose. 
Plagia, however, may 
be distinguished from all the other genera of the group by the short bristles on some of the longitudinal veins, 
and by the peculiar oblique position of the posterior cross-vein. 
