MAY FLIKS AND MIDGES OF XEW YORK 29 



of pl.'JT of Katon's Monograph \vilh those of m\ pi. ." ;iml <! will 

 show (he dose agreement of it with O h. a 1 b o in 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 Pol y m i t a r < y s v i r g o 

 (Hiv. This was suspected by Katon and yet he allowed the adult 

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

 less the nymph Jolia furnished a reason for including 

 O 1 i g o n e u r i a and its allies in the E p h e in e r i n a e also. 

 The nymph of O 1 i g o n e u r i a is certainly nearest C h i r o- 

 t e ne te s of all forms hitherto described; and it has not yet 

 l.eeii 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 he expressed as fol- 

 lows: 



1 Subfamily Ephemerinae;a fairly homogeneous series. 1 



2 Subfamily H e p t a ge 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: 



ft) The group of Oligoneuria (Oligoneuria to Homeoneuria 



of Eaton: pis. 3 and 20 of bis monograph); five genera, represented 



in tropical America and in the old world 

 M The group of Baetis, 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 

 (7) 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 o m a only 

 c) Tin' uTuiip of tin- 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 1807. 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. 

 20:247. 1900). This key was then already in use by entomological stu- 

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

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

 of them. 



