406 NEW YORK STATE MUSEUM 



The plots were strikingly unlike in that there were fewer species in the 

 second, fewer dragon fly and May fly nymphs and dipterous larvae. 

 They differed farther most strikingly in the kind of mollusks present : the 

 Campeloma decisumof the second plot was absent from the first ; 

 it is common in tlie pond above. The long-horned leaf beetles, D o - 

 n a c i a, of the second plot were a special feature which belonged with 

 the special habitat furnished by the bur reed growth. Two photographs, 

 reproduced in plate 9, show these insects in their natural positions on the 

 plant. 



These are fragments — mere fragments — of real knowledge of the life of 

 this stream. While not without interest in themselves, they seem to me 

 chiefly valuable in their suggestiveness of possible knowledge to be gained 

 by farther application of these methods. 



Count of dragon fly exuviae. In the midst of the hatchery grounds 

 there was a fish pond, made by impounding the creek, with its eastern 

 side boarded up to a hight of 15 to 20 inches above the level of the 

 water, for a distance of perhaps 20 yards. The boards were rough, and 

 suited dragon fly nymphs very well as a place to transform. It was an 

 exceptionally favorable place in which to learn something of the numbers 

 of dragon flies to emerge from a given water area ; for the cast skins 

 were all left in plain view. The other bank was not boarded, and while 

 the cast skins appeared to be about as common there, one could not 

 be sure of finding all of them. A view of this pond, looking up stream, 

 is presented in plate 6. 



Conditions here were right for determining the yield of this strip of 

 water in dragon flies of those species whose period of transformation falls 

 entirely within the last three weeks of June at Saranac Inn. I do not 

 say half the yield, because it seems fair to presume that half were on the 

 other bank, where their discovery was not so easy. Nymphs when ready 

 to transform are blind, and wander about till they find a bank, showing 

 no preference as to which bank it is. These time limits are taken be- 

 cause they are the only narrow ones that will include the entire trans- 

 formation period of a considerable number of species. 



I found quite a number of these skins already chnging to the boards on 

 my arrival June 12, for the season for transformation for some of these 

 species was already at hand. It appears fair to assume, however, that I 

 obtained practically all the skins that had been left there, because they 

 had apparently not been disturbed at all ; they stick very tightly, so that 

 moderate winds and even rain do not quickly dislodge them. The weather 

 previous to my arrival had been clear and calm, and the season of trans- 



