52 



NEW YORK STATE MUSEUM 



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which they dwell are very diverse. The conditions, of adult life 

 are, however, much the same in all; and we find the adults much 

 more alike. The beginner will certainly find 1 them much more 



difficult to distinguish, and would 

 do well to study nymphs and adults 

 together. The critical diagnosis of 

 the species will doubtless rest on the 

 highly individualized genital arma- 

 ture of the male. A suggestion of 

 the strength and definiteness of the 

 characters presented by these parts 

 may 'be had from reference to the 

 accompanying figure of the male for- 

 ceps and inner appendages of Ecdyurus maculipennis 

 (fig.10). These project strongly from the ventral side of the apex 

 of the abdomen, and are easily separated therefrom in fresh or 



Fig. 11 Tarsal claws of nymphs of 

 Heptageninae; w, of Hepta- 

 genia interpuuctata Say; x, 

 of Rhithrogena elegantala 

 Etn. ? ; y, of Iron sp ? from Coy 

 Glen, Ithaca; z, of Ecdyurus 

 maculipennis Walsh; hind 

 claws in each case; middle ones 

 would be similar ; front ones some- 

 times different 



Fig. 12 Labra of nymphs of Hepta- 

 geninae ; h, of I r o n sp ? from Coy Glen, 

 Ithaca; i, of Rhithrogena elegan- 

 tula Etn.?; j, of Ecdyurus maculi- 

 pennis Walsh; k, of Heptagenia 

 interpunctata Say 



Fig. 13 Mandibles of nymphs of Hepta- 

 geninae; c, of Rhithrogena elegan- 

 tula Etn. ?; d, of Iron sp? from Coy 

 Glen, Ithaca; e, of Ecdyurus maculi- 

 pennis Walsh; f, of Heptagenia 

 interpunctata Say 



alcoholic specimens by a longitudinal snip with a pair of fine 

 scissors. They may then be permanently mounted on a slide as 

 microscopic preparations so as to give a square ventral view. 

 It is from preparations so made that all the figures of the male 

 appendages in this paper have been drawn. 



