16 NEW YORK STATE MUSEUM 



I have in hand a stud}* of the venation of the H e m e r o - 

 biidae. This material, especially II e m e r o b i u s amicu- 

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

 deutalis from Illinois (which I have recently received from 

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

 lected at Saranac 1 Inn, Ithaca and in Illinois, have 1 1n-own some 

 lig-ht on the evolution of the peculiar Hemerobian type of venation. 

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

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

 c ul us Fitch and II. occidental is Fitch represent 

 two stages in the (volution of the type which should be marked 

 by generic rank. I therefore < haracteri/.e them here and in the 

 form of i key, bemuse the key to 1 1 e in e r o b i i d a e in bulletin 

 47 was not made complete for our genera : 



KEY TO THE GENERA OF HEMEROBIIDAE 



a Brandies of UK- radial sector arising (/. ' .. sepa- 

 rating fi'oni vein II,) by a common stalk 



b With three ocelli D i 1 a r 



1)1) With no ocelli 



c Humeral rmssvein (the basal costal cross- 

 vein) simple and not recurrent 

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



<hl All of the branches of vein Cn, simple C 1 i m a c i a 



cc Humeral erossvein recurrent and bearing a 



number of brandies on its outer side 



<7 Suheosta and radius separate at the tips.. Polystoechotes 

 thl Snbeosta and radius conjoined at the tips. . B e r o t h a 



an 1! ranches of the radial sector appearing to arise 



separately from vein R, 



b Humeral crossvein unbranched and not recur- 

 rent (pl.3, figs. 1 and 2) M i c r o m u s 



1>1) Humeral crossvein recurrent and with brandies 



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+2 is well separated from the base 

 of the radial sector, with a distinct 

 crossvein between 



(1 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 



Spad'obius n. gen. type H. occidental! s Fitch 



