306 



NORTH AMERICAN DIPTKRA. 



forked at the end. The larvae of species of Notiphila have 

 been observed in the stems of water plants; those of Hy- 

 drellia in the sap of trees, in the parenchyma of the leaves 

 of Lemna, on A/isma, etc., those of Pelina, Ephydra, 

 Parydra, etc., in water, often salt or alkaline. 



The bristly spine of the second anteunal joint is some- 

 times not easily discernible. I have included in both 

 sections some of the genera about which doubt may arise. 



Fig. 121. Ephydridae. 28, Beckerieila bispinosa, wing; 29, Parydra bituber- 

 culata, head: 30, Mosillus, sp. wing; 31, Mosillus, sp. liead; 32, Scatella stag- 

 rial is, wing; 33, llythea ftavipes, wing; 34, Ilyihea flavipes, head; 35, Pelomyia 

 occidentalis, head; 3d, Paralimna, sp. middle tibia; 37, Genus ? (Illinois). 



TABLE OF GENERA. 



1. Second basal and anal cells complete ; auxiliary vein distinct 



throughout; third antennal joint spherical. . . Canace. 



Second basal cell confluent with discal cell; aiixiliary vein coales- 



cent distally with first vein. ...... 2 



2. Antennae small, inserted remotely in cavities, the arista atrophied; 



eyes pubescent; bristleless flies (26, 27). . Lipochseta. 

 Not such flies. 2 



3. Second joint of antennas with a spinous bristle at upper distal cor- 



ner. ........... 4 



Second antennal joint without such bristle. 16 



