1911] May-Flies of Fall Creek, N. Y. 101 



all alike, they have been forced into a series of similar adapta- 

 tions. The principle feature of these adaptations are: a gen- 

 erally depressed body; dorsally placed eyes and flaring margins 

 to the head; spreading legs with flattened femora and lateral 

 pectinations on the claws; a series of over-lapping gill lamellae, 

 and flat widely diverging caudal setae. 



Heptagenia interpunctata Say. 



Five species of the genus Heptagenia were collected and 

 reared during the summer, but only the very common H. inter- 

 punctata will be listed until further work can be done upon 

 them. H. interpunctata was common from April 30, when I 

 found nearly grown nymphs beneath the flat stones in a trib- 

 utary of the creek up to August 1, after which little collecting 

 was done. During this time many emergings were observed, 

 the greater number occurring between two and five o'clock in 

 the afternoon. 



Ecdyurus maculipennis Walsh. 



Associated with Heptagenia and Epeorus, but with a pref- 

 erence for more gently flowing water, Ecdyurus maculipennis 

 is a frequent dweller in the quieter border water of swift cur- 

 rents. My first collections are dated June 3. From this date 

 till July 25 it was a common associate of Heptagenia and 

 Epeorus, slightly smaller and a swifter runner than either of them. 

 It also bears transportation and change of water with greater 

 hardiness. 



Iron fragilis. 



The nymph of this species was described by Prof. Needham 

 in 1905. In addition to this description there have been but 

 two records of this genus in North America, Iron nitidus,* 

 Oreg. Cal. and I. longimanus.f Colorado. The first nymphs of 

 this species collected during the summer were found on May 9, 

 in Coy Glen, the stream from which Prof. Needham's speci- 

 mens were taken. Here thick growths of Cladophora and 

 diatoms support an abundant May-fly population. The 

 nymphs live in the swiftest water, on the under side of the stones, 

 in the falls, or on the smooth rock floor. A census of the inhab- 



* Iron nitidus Eaton. Rev. Monog. 246, 1885. Oreg. Cal. Banks, Cat. Ncur. 

 Insects. Am. Ent. Soc. '07. 



t I. longimanus, Eaton, Ent. Mo. Mag. XVIII, 26, 1881. Rev. Monog. 245, 

 1S85. 



