AMERICAN NEUROPTERA. 137 



A REVISION of the NEARCTIC CHRYSOPIDjE. 



BY NATHAN BANKS. 



Every entomologist knows Chrysopa ; for there are few regions in 

 the world where insects abound unrepresented by Chrysopa, or some 

 allied genus. Throughout our country Chrysopa is represented in 

 every locality by several species; and everywhere there is at least 

 one species which may be reckoned among the " common insects." 

 The delicate green color, the beautiful golden eyes, and, above all, 

 the peculiar odor of certain species have made Chrysopa familiar to 

 every collector of insects. 



The family Chrysopidse is distinguishable from the other families 

 of Neuroptera by the following characters: 



Mouth not rostrated, no anal space to the hind wings; anterior 

 legs simple (not raptatorial) ; wings bare (not powdered); antenna' 

 setiform ; costal space of anterior wing is narrow at base, no recur- 

 rent vein, transverse veinlets in gradate series. The family is 

 closely related both in structure and in larval habits with the Hem- 

 erobiiihe, but a colorational character will always separate them ; the 

 Chrysopidse are usually mostly green, while the Hemerobiidae arc 

 never green, but more or less brown. There are various structural 

 characters which separate the two families. The pronotum in Chrys- 

 opidse is usually as long or longer than broad, in the Hemerobiidse 

 it is plainly broader than long. The wings of the Chrysopidse have 

 many more cross-veins than in the Hemerobiidse; the result is that 

 most of the cells in a Chrysopid wing are rarely more than twice as 

 long as broad, while in the Hemerobiid wing the cells are three 

 times and usually four to six times as long as broad. In the 

 Chrysopidse there is but one radial sector which is connected back 

 to radius by at least six cross-veins. In the Hemerobiidse there are 

 usually several radial sectors, and the last is connected back to the 

 radius by only one to three cross-veins. In the Chrysopidse the 

 radial sector of the hind wing is united for some distance to the 

 median vein ; this does not obtain in the Hemerobiidse. 



The Chrysopidse are insects of rather small size with comparatively 

 large wings. At rest, the wings are held roof like over the body, 

 and the antennae are extended outward and forward. Their flight 



TRANS. AM. ENT. SOC, XXIX. (18) APRIL, 1903. 



