30 
when situated near the middle of the length of the segment, and mar- 
ginal when located near its posterior margin. 
The veins and cells of the wings are called by the same terms as in 
the other families of Diptera, except that the first posterior cell is com- 
monly called the apical, and the portion of the fourth vein beyond the 
bend is sometimes termed the apical crossvein. 
TABLE OF (JE.XERA. 
The only attempt at publishing a synoptic table, comprising all of the 
genera reported as occurring in North America, is that by Mr. 0. EL T. 
Town send, in the Proceedings of the Entomological Society of Wash- 
ington ' and in the Transactions of the American Entomological Soci- 
ety.- That in the former publication is a reprint of the table given by 
Dr. Schiuer, 3 and that in the latter a reprint of the one by F. M. van 
derWulp, 4 both modified so as to comprise only the North American 
genera. As the ajathor did not have access to specimens of many of 
these genera, and as the characters he uses are in many cases irT>t of 
specific, much less of generic, value, the result is not altogether satis- 
factory, and I have therefore constructed an entirely new table, 
which, however, includes only those genera from America north of 
.Mexico of which I have examined representatives. A list of the remain- 
ing genera reported from this region is given at the end of the table. 
In some cases doubt will arise as to which section a given genus 
should be referred, but in such cases, at least so far as they occur to 
the writer, the genus is placed in both sections: 
1. Abdomen provided with true macroohaetse 8. 
Abdomen destitute of macrochaetae, apical cell ending at or aear the extreme 
wing tip 2. 
2. Upper side of abdomen very convex, abdomen subhemispherical, sides of face 
bare 3. 
Upper side of abdomen flat, or the abdomen elongated and cylindrical 4. 
3. Antenna not reaching lower third of face (p. 12) Cistogaster, 
Antennae reaching lowest fifth of face, or even lower (p. 43) Grymnosoma, 
1. Hind tibia- outwardly not cilia to with scales 5. 
Hind tibiae ciliate with nearly erect scales, sides of face bare. .(p. 47) Trichopoda. 
5. Sides of face bare (i. 
Sides of face bristly, third and fourth veins almost equally converging toward 
their tips, which meet or almost meet each other (p. 1!)) Gymnophania. 
C. Proboscis at most slightly longer than the head, geniculate near the base onlv, 
antennae at most reaching slightly below middle of face, apical cell closed, the 
petiole at least twice as long as the small crossvein 7 
Froboscis bristle like, almost as long as the body, geniculate near the base and 
also near the middle (p. 49) Eusiphona. 
1 Vol. II, pp. 92 to 99; April 2, 1891. 
* Vol. XIX, pp. 134 to 141 ; June. 1892. 
"Fauna Austriaca, Diptera, Vol. I, pp. LXX to LXXI; 1K<;2. 
4 Biologia Centrali-Amerieana, Diptera, Vol. II, pp. 5 to 7, and 11 to 44 ; 1888 and 1890. 
