E. T. CRESSON, JR. 63 



Represented by nineteen specimens: Cartago, October 27 to 

 May 17; Bonnefil Farm, Rio Surubres, October 20; Over mud at 

 Turrucares, December 22; Beaches of back channel of Rio 

 Reventazon at Cachi, March 7; Stagnant pool, bank of Rio 

 Reventazon near Juan Vinas, March 10; Brook Toyogres on 

 southern slope of Irazii, June 6. 



GASTROPS 



1897. Williston, Kans. Univ. Quart., vi, 3. 



This genus is characterized by the subhemispherical protuber- 

 ance on the median area of the face, and the portion below falling 

 vertically. The scutellum in the known species has two apical 

 tubercles. The abdomen is broad, rather circular in outline, 

 with margins revolute and the surface roughened like a rasp file. 

 In many respects its species suggests Parydra. 



Only one, the following species is known from Costa Rica. 



Gastrops nigra Williston PI. Ill, fig. 10. 



1897. Gastrops niger Williston, Kans. Univ. Quart., vi, 3, (Brazil). 



Black, with antennae and tibiae more or less pale. Thorax 

 polished, not dusted or vittate; scutellum convex and wings 

 immaculate. 



Twenty specimens collected from the following localities: 

 Stagnant pools on banks of Rio Reventazon, Cachi, IMarcli 10; 

 over brook at edge of forest, Juan Vinas, May 3; over mud at 

 small stream north of Rio Siquiares, December 19 to 22. 



PSILEPHYDRA 



1914. Hondel, Suppl. Ent., iii, 99. 



This genus is characterized by the peculiar development of the 

 face, which is large, broadly convex, extending well down, appear- 

 ing somewhat hemispherical. There are no lines or marks de- 

 fining the orbital areas, cheeks, foveae and such. There are no 

 characteristic facial bristles, but the entire face is clothed with 

 short, decumbent pile and scattered, suberect hair-like bristles. 

 Its systematic position is apparently somewhere in the Ephy drinae. 

 The following species is the only one known besides its congener 

 from Formosa. 



TRANS. AM. ENT. SOC, XLIV. 



