192 NEW YORK STATE MUSEUM 



Caenis diminuta. This little white dusk-flyer abounds in 

 every submerged weed patch, its close clinging, flat-bodied, silt- 

 covered nymphs adhering closely to the fallen stems among which 

 they clamber. It has already been mentioned in the preceding pages 

 as swarming into our trap lanterns, as being found in the hatchery 

 windows after emergence from the ,fish troughs, and as constitut- 

 ing a very considerable portion of the food of young sunfishes. It 

 was abundant throughout July and August. 



Tricorythus allectus. Since I described this species from 

 Ithaca in 1905 [N. Y. State Mus. Bui. 86, p. 47] as Caenis 

 a 11 e c t a , I have concluded that it should more properly be re- 

 ferred to the genus Tricorythus.^ Since that date I have found it 

 abundant in two new localities, at Watertown, Massachusetts, in 

 the summer of 1906, where spiders' webs on the bridges across the 

 Charles river were draped with innumerable tangled specimens, 

 and at Moose river, behind the hatchery at Old Forge. One of its 

 favorite swarming places was the open area above the pole bridge 

 shown in the middle of the photograph reproduced in plate i. Here 

 it swarmed at midday filling the air like snowflakes, with dragon 

 flies, and robber flies lurking around the edges of the swarm, 

 capturing as many specimens as they could eat. 



Choroterpes basalis. This pretty red brown species I ob- 

 served several times in small companies swarming about the balsam 

 firs on Wintergreen point in August. 



Habrophlebia vibrans n. sp. This delicate little reddish brown 

 species I captured by hundreds near the outlet of Bald Mountain 

 pond, where the brook crosses the road and begins its descent 

 among the fern clad boulders. White winged companies of them 

 were dancing up and down under the birch canopies, the lowest of 

 them within reach of my net. I have been unable to determine from 

 Bank's description and figure of H. americana [Ent. News. 

 1903, II 1235], what relation this species may bear to that one from 

 New Jersey. The nymph of that one as described by Berry (Amcr. 

 Nat. 37:27-29, 1903) does not belong to this genus at all: it is a 

 typical Leptophlebia. I present herewith a figure of the 

 venation [pi. 10, fig. i] and of the appendages of the male, and 

 add the following further characterization of the male imago, the 

 onlv form found : 



^ Sec also Cockercll & Gill. Tricorythus, a genus of Mayflies. Univ. of 

 Col. Studies 3:135-37. A paper that has appeared since the above was 

 written. 



