MAY FLIES AND MIDGES OP NEW YORK 29 



of pl.27 of Eaton's Monograph with those of my pi. 5 and 6 will 

 show the close agreement of it with C h. a 1 b o m a n i c a t u s, 

 and demonstrate its generic position. The adult which Joly 

 furnished Eaton as having been bred from this species of nymph 

 was doubtless a poor specimen of Polymitarcys virgo 

 Oliv. This was suspected by Eaton and yet he allowed the adult 

 to determine the position of the species in his system. Doubt- 

 less the nymph Jolia furnished a reason for including 

 Oligoneuria and its allies in the Ephemerinae also. 

 The nymph of Oligoneuria is certainly nearest C h i r o- 

 tenetes of all forms hitherto described; and it has not yet 

 been shown that the very degenerate imagos may not as well 

 have descended from this part of the series, and belong in the 

 B a e t i n a e as here understood. My present ideas of the 

 major natural complexes of the order may be expressed as fol- 

 lows: 



1 Subfamily E p h e m e r i n a e ; a fairly homogeneous series.^ 



2 Snibfamily H e p t a g e n i n a e ; a very homogeneous series. 



3 Subfamily Baetinae; a very heterogeneous series, only 

 definable as lacking the characteristics of the other two, and in- 

 cluding five fairly distinct groups, some of which may be found 

 worthy to rank as equivalents of 1 and 2 above: 



o) The group of Oligoneuria (Oligoneuria to Homeoneuria 

 of Eaton; i^ls. 3 and 20 of his monograph); five genera, represented 

 in tropical America and in the old world 



b) The group of B a e t i s , including all our genera of Baetinae 



except B a e t i s c a , and many exotic genera 



c) The group of B a e t i s c a , including B .a e t i s c a only 



d) The group of P r o s o p i s t o m a , including the exotic P r o s o p i s - 



t m a only 



e) The group of the nameless Chilean nymph figured on pi. 53 of Eaton's 



Monograph 



^These three subfamilies, which I Indicated parenthetically in my key to 

 nymphs published in bulletin 47, I had already recognized in 1897. Shortly 

 afterward my friend Mr C. A. Hart, of the Illinois State Laboratory of 

 Natural History, sent me a manuscript key in which these major divisions 

 were plainly indicated, and also a number of minor divisions, including the 

 tribes Baetini and Caenini of Banks (Trans. Amer. Ent. Soc. 

 26:247. 1900). This key was then already in use by entomological stu- 

 dents at the University of Illinois, the basis for these divisions having 

 been recognized independently and, perhaps, prior to my own recognition 

 of them. 



