1910.| NATURAL SCIENCES OF PHILADELPHIA. 537 



to North Carolina. It is a species of low swampy areas, though 

 usually more wooded than that frequented by inconstans. In New- 

 York and New England it flies from May 22 to October 1, being 

 abundant in late May and early June, reappearing the latter half of 

 July and being common throughout August and early September. 

 The late summer specimens probably represent a new species, the 

 females having the wings very reduced in size. 



Tricyphona auripennis Osten Sacken. (Plate XXVIII, fig. 49.) 



Canadian life-zone of the northeastern United States, known only 

 from New Hampshire, Massachusetts (the type-locality) and New 

 York. It flies in June. The only specimens ever seen alive by the 

 author occurred at Indian Castle, Herkimer County, New York, 

 June 10 to 13, 1915; they were found sitting motionless on the 

 perpendicular face of a small cliff, lurking in small crevices of the 

 rock. The cliff is low, of Utica shale, completely saturated by 

 percolating water and well-shaded by large hemlocks, arbor vitae,. 

 yellow birch, mountain maple, Cornus circinata, etc., and with a 

 sparse vegetation of Impatiens biflora, Geranium Robertianum, 

 Collinsonia canadensis, Cystopteris bulbifera and Equisetum arvense. 



Tricyphona hyperborea Osten Sacken. (Plate XXVIII, fig. 50.) 



A fly of the Hudsonian and possibly the Canadian life-zones of 

 northeastern America and still very rare in collections. It was 

 described from Labrador, and a few specimens have been taken on 

 Mt. Washington, New Hampshire; these specimens are in the col- 

 lections of the Boston Society of Natural History and the United 

 States National Museum. 



Tricyphona katahdin Alexander. (Plate XXVIII, fig. 51.) 



Canadian life-zone of the northeastern United States, a late 

 summer species flying during the latter half of August. 



Tricyphona vernalis Osten Sacker. (Plate XXVIII, fig. 52.) 



Canadian and Canadian-Transitional zones of the northeastern 

 United States. One of our early-flying species, though appearing 

 later, as a rule, than paludicola. It ranges from Maine and New 

 Hampshire south (in the mountains) to Georgia, and is found along 

 small streams, temporary and permanent, where the water runs 

 rapidly. The flies may be swept from vegetation or are found in 

 small swarms of eight to ten individuals near the water. In New 

 York and New England it is on the wing in late May, abundant in 

 June and persisting into July. Further south it flies in April or 

 even the last of March, reappearing in late September. 



