34 Psvr.he [February 



SPECIES OF THE GENUS GAURAX OF THE EASTERN 

 UNITED STATES. 



By Charles W. Johnson, 

 Boston Society of Natural History. 



These interesting little flies are only occasionally taken in 

 sweeping but can often be obtained in some numbers in breeding 

 other insects, as they differ from other members of the family 

 Oscinidse, in feeding upon insect remains instead of vegetable 

 matter. They are not parasitic but inquilinous or more properly 

 speaking scavengers, the larvae feeding upon the cast-off skins 

 of caterpillars, pupae cases and spider eggs. 



Gaurax anchora Loew has been bred from the cocoons, etc., of 

 Samia cecropia, Hemerocampa leucostigma (Tussock moth); 

 Porthetria dispar (Gypsy moth), and egg cluster of Corydalis 

 cornutus. Gaurax aranece Coq., of California was reared from the 

 egg-sac of a spider (Argiope riparia), and Gaurax lancifer Coq. 

 of the West Indies, also from egg-sacs of spiders. The habits of 

 the other species are unknown. The Gaurax ephippium Zett., re- 

 ferred doubtfully to this genus by Coquillett in the list of Diptera 

 of Beulah, New Mexico, (Trans. Amer. Ent. Soc, XXIX, 106, 

 1903) is a Chlorops according to European authors. 



In studying the New England species collected during the past 

 few years, I find one new species, making four from this region. 

 They may be tabulated as follows: — 



1 Thorax yellow, with a black dorsal mark 2 



Thorax entirely black; scutellum yellow montanus Coq. 



2 Wings entirely hyaline 3 



Wings with the basal half smoky black obscvripennis sp. n. 



3 Thorax with a narrow anchor-shaped mark; scutellum also marked with 



black anchora Loew 



Thorax with a broad mark, the posterior edge tridentate; scutellum entirely 

 yellow f estiva Loew 



Gaurax montanus Coquillett. 



Aside from the type locality, White Mountains, N, H., I have 

 collected this species at Norwich, Vt., July 8, 1908. 



