16 NEW YORK STATE MUSEUM 



I have in hand a study of the venation of the H e m e r o - 

 b i i d a e . This material, especially Hemerobius a m i c u - 

 1 u s Fitch, and another of Fitch's rare species, H . o c c i - 

 d e n t a 1 i s from Illinois (which I have recently received from 

 Wisconsin), together with other species of H e m e r o b i u s col- 

 lected at Saranac Inn, Ithaca and in Illinois, have thrown some 

 light on the evolution of the peculiar Hemerobian type of venation. 

 My study will in due time be published elsewhere when it is com- 

 pleted; and the results to be noted here are merely that H . a m i - 

 culus Fitch and H. occidentalis Fitch represent 

 two stages in the evolution of the type which should be marked 

 by generic rank. I therefore characterize them here and in the 

 form of a key, because the key to Hemerobiidae in bulletin 

 47 was not made complete for our genera : 



KEY TO THE GENERA OF HEMEROBIIDAE 



a Branches of the radial sector arising (i. e., sepa- 

 rating from vein RJ by a common stalk 



& With three ocelli D i 1 a r 



&& With no ocelli 



c Humeral crossvein (the basal costal cross- 

 vein) simple and not recurrent 



d Some of the branches of vein Cu x forked. . S i s y r a 



dd All of the branches of vein CUi simple. ... C 1 i m a c i a 



cc Humeral crossvein recurrent and bearing a 



number of branches on its outer side 



d Subcosta and radius separate at the tips.. Polystoechotes 

 dd Subcosta and radius conjoined at the tips. . B e r o t h a 



aa Branches of the radial sector appearing to> arise 



separately from vein Rj 



& Humeral crossvein unbranched and not recur- 

 rent (pl.3, figs. 1 and 2) Micromus 



&& Humeral crossvein recurrent and with branches 



on its outer side 



c First division of the radial sector arising 

 before or opposite the basal subcostal 

 crossvein ; in the hind wing the vein 

 Mj+a is well separated from the base 

 of the radial sector, with a distinct 

 crossvein between 



d A closed cell in the first fork of the radius 

 before the base of the second division 

 of the sector (pl.2, fig.2); front coxae 

 longer than the femora 



S p a d o b i u s n. gen. type H. occidentalis Fitch 



