506 REPORT OF THE 



These insects are very interesting, not only on account of their value as food 

 for fishes, but also because they present a peculiar phenomenon, a pseud-imago or 

 sub-imago stage. As previously stated, the young of these insects live in the water, 

 and at the time of their emergence the nymphal skin is ruptured and the May-fly 

 crawls forth, flies some distance, alights, and then, to the surprise of one who has 

 never observed it before, deliberately proceeds to cast off another skin, which is 

 known as the pseud-imaginal skin. It is a perfect case of the insect, covering wings, 

 antennee, anal filaments and legs, and in places where May-flies are at all abundant 

 these pseud-imaginal envelopes are frequently very conspicuous. 



Comparatively few May-flies were studied by Dr. Needham at Saranac Inn, but 

 abstracts from some of his biologic notes on a few species may prove of interest. 



Hcptagcnia pnlcliclla Walsh. Imagos of this species, represented in natural 

 colors in figure 15, plate i, were found to be common during June, July and the 

 greater part of August, being most abundant in June, and mostly males were taken 

 in trap lanterns whenever the weather was favorable, and others were seen flying 

 about at twilight. The species was not often seen though exceedingly common. 

 The nymphs, plate i, figure 16, w^^re found abundantly in Little Clear Creek, 

 especially in the more rapid places, clinging closely to the flat surfaces of boards, 

 sticks, etc. They were easily collected by lifting these obstructions and picking 

 them off with forceps. 



Bactis pygmceaYi-a.^(i.x\. This species, like the preceding, was found commonly 

 in the hatchery windows, and was often taken in small numbers in trap lanterns, 

 though seldom seen at large. Imagos occurred sparingly through the earlier part 

 of the season, but they became very abundant in August. They are represented at 

 figures 13 and 14 on plate i. Nymphs of this species were found most abundant 

 among the cases of Siinuliiiiii pupae in swiftly flowing water, and few could be 

 taken at any time from the hatchery troughs. This is the daintiest and one of the 

 prettiest of our May-flies. 



Sipliluriis alternatus Say. This handsome brown species, plate 2, figure 7, was 

 obtained by Dr. Needham by rearing from the nymphs, figures 5 and 6 on plate 2,. 

 which were not uncommon among the debris of floating brush wood in shallow 

 water by the outlet of Little Clear Pond. The nymph is a graceful creature and 

 exceedingly agile (figures 5 and 6 of plate 2). The beautiful fringes on the abdom- 

 inal setae constitute a powerful tail fin which sends the nymph through the water 

 with a speed the eye can hardly follow. A great many specimens were taken in 

 shallow water behind a large hummock overgrown with cattails {Typhd) to the north 

 of the outlet of Little Clear Pond. These transformed July 21, 22 and 23, remained 



