1916.] NATURAL SCIENCES OF PHILADELPHIA. 527 



Ninth sternite almost straight across, or slightly narrowed to the 

 truncated apex. 



Gonomyia (Gonomyia) unicolor Alexander. 



Gonorhyia unicolor Alexander; Proceedings of the United States National 

 Museum, vol. 44, p. 507, PI. 66, fig. 15 (1913 



An extra-limital species (Guatemala, Central America) included 

 here to complete the data. 



The male hypopygium (Plate XXX, fig. 89) with the pleurites 

 moderately stout and elongated, the dorsal angle not produced; 

 ventral pleural appendage (v) a double lobe, dark colored, sub- 

 chitinized, the inner arm stout-cylindrical with the tip acute and 

 the inner side with two or three hairs; the outer and more ventral 

 arm slender, curved and bearing near the tip two stout divergent 

 hairs; dorsal pleural appendage (d) a subcylindrical fleshy lobe from 

 an enlarged base, at the apex with two powerful bristles; cephalic 

 or inner face with four small hairs that are evenly spaced. Ninth 

 tergite almost straight across or slightly concave. Penis-guard 

 (Plate XXX, fig. 88) seen from beneath, a powerful, quadrangular 

 chitinized base whose caudal angle is a ventrally directed hook, the 

 base subtended on either side by short gonapophyses (g) that end 

 in a sharp, conical spine ; from above and dorsad of the quadrangular 

 base arise two cylindrical, pointed, chitinized arms that are diver- 

 gent. 



- 



Gonomyia (Gonomyia) mexicana Alexander. 



Gonomyia mexicana Alexander; Canadian Entomologist, vol. 48, pp. 321, 322 

 (1916). 



An extra-limital species described from Cordoba, State of Vera 

 Cruz, Mexico, May 8, 1908 (Knab). 



The male hypopygium (Plate XXX, fig. 91) with the pleurites 

 elongate, though rather stout; ventral pleural appendage (v) a long, 

 pale lobe, subcylindrical, blunt at the apex and bearing sparse, 

 elongate hairs; second pleural appendage strongly chitinized, the tip 

 acute, curved; dorsal pleural appendage (d) rather short, cylindrical, 

 fleshy, the cephalic or inner angle of the apex with two powerful 

 bristles; caudal or outer angle of the apex with two smaller hairs. 

 Ninth tergite rather short, the caudal margin straight or nearly so. 

 Penis-guard (Plate XXX, fig. 90) very long and pale, the apex bifid 

 by a deep U-shaped notch, each lobe provided with long hairs; on 

 the ventral face arises a slender, rod-like, median appendage, sparsely 

 short-hairy at the apex and down the ventral face; the divergent 

 subtending arms are slender, somewhat flattened, the apex produced 



