190 NEW YORK STATE MUSEUM 



through July and August. It emerged in considerable numbers, as 

 shown by the preceding table, from my tent trap, 6 square feet of 

 the bottom of Beaver Meadow brook, yielding 271 specimens in a 

 single month. This is the species previously mentioned as giving 

 such a beautiful example of the May fly dance under the birch 

 trees at the crossing of the Beaver Meadow brook by the Adiron- 

 dack League Club road. 



Chloeon mendax and C. vicinum,. These two delicate little 

 May flies (and a third apparently und escribed) were obtained -with 

 a trap lantern near the foot of First lake just after nightfall. Dr 

 Betten and I rowed up to First lake on several evenings that bid 

 fair to furnish good trap lantern collecting, and just at nightfall 

 before the chill that is characteristic of the Adirondack evening had 

 settled down, a few of these specimens came to light to reward our 

 effort. Later in the evening no more could be obtained, but we had 

 reason to believe that they were not uncommon at that place. 



Ephemerella dorothea n. sp. This species lives in Beaver 

 Meadow brook, amid the soil gathering moss that covers the stones 

 there, as described in the account of our tent trap. Adults were 

 obtained only by rearing them, and this notwithstanding their abund- 

 .ance, as evidenced by the abundance of their »nymphs at that place. 

 We did much collecting along the banks of that brook, sweeping 

 the vegetation with nets, all up and down -it, and not a single adult 

 specimen was encountered. It was the sort of May fly easily to 

 be overlooked, not alone on account of its habits, but also because 

 of its general appearance. The best specimens that I have obtained 

 of these are when fully mature, exceedingly fragile and have very 

 little color. They look at first glance much like poor specimens of 

 some of the stronger species. I append a description of both 

 nymphal and adult stages. 



Imago. Length, 5 to 6 mm; expanse, 15 to 18 mm; setae of 

 the female, 8 mril; of the male, 8 to 9 mm; first femur of male,' 

 7 mm; of the female, 4^ mm; a small yellowish species, pale even 

 when fully mature, somewhat darker on the dorsum of the head 

 and the abdomen, with hyaline iridescent wings, and pale yellowish 

 white legs; infuscated only on the tips of the tarsi. Caudal setae 

 white ; forceps of the male, stout, the long second segment regularly 

 tapering to near the apex, there sudde;ily internally dilated in a 

 rounded knob. The first and third joints of the male forceps are 

 of about equal length, each being about ^ of the length of the 

 second joint, terminal joint subspherical. The ninth sternite of 

 the female is produced in a broadly truncated lobe which projects 

 posteriorly to the level of the posterior apex. The foretarsus of 



