98 ENTOMOLOGICAL SOCIETY 



Fam. Gymnosomatidae. 



Cistogaster is placed in the Phasiidtz by Brauer and v. Ber- 

 genstamm. I consider the number of abdominal joints a 

 better character than the slight facial differences employed by 

 these authors for family characters, and retain it with Gymno- 

 soma. 



The larvae of these flies, so far as known, are parasitic on 

 plant-bugs. 



Antennae reaching almost or quite to the epistoma ; abdomen globose, 

 having a decidedly inflated or swollen appearance ; apical cell 

 closed andpetiolate gen. Gymnosoma 



Antennas reaching only half way to the epistoma ; abdomen short oval, 

 sometimes nearly round ; apical cell petiolate, closed in the 

 border, or even narrowly open gen. Cistogaster 



Cistogaster L/atreille, Cuv. Regne An., V. (1829.) Nova Scotia ; 

 United States. The larval habits of this genus are unknown. 



Gymnosoma Meigen, Illig. Mag., II, 278. (1803.) Nova Scotia; 

 United States. The larvae, on the authority of v. Heyden, are parasitic 

 in the bodies of Pentatomidcz (Schiner). 



It is rather remarkable that neither of the above genera 

 has ever been found in Mexico or Central America, although 

 Gym.filiola H. I/w. has been identified by Mr. v. Roder from 

 Porto Rico. With this single exception, the family seems to 

 be peculiar to the north temperate zone. 



Fam. Ocypteridae. 



The larvae of these flies have so far been found parasitic 

 only on Pentatoma and Cassida. 



1. Apical cell open (sometimes very narrowly) 2 



Apical cell closed and petiolate ; third antennal joint flattened, once 



or twice as long as the second ; epistoma more or less promi 

 nent ; apical cross-vein angulate at its origin gen. Ocyptera 



2. Third antennal joint longest 3 



Second antennal joint longer than the third 4 



3. Third antennal joint only about three times the length of the second, 



widened into an equilateral triangle in the tf, much widened at 

 the apex in the 9 > hypopygium not bent under the abdo 

 men gen. Lophosia 



