NEUROPTERA 



301 



As it would be impracticable to apply to these serial veins names 

 indicating their composition, they have been termed the pseudo- 

 media or vein M' and the pseudo-ciibitus-one or vein Cui', re- 

 spectively (Fig. 340, ]\r and Cu/). 



Fig. 341. — Tracheation of the wings of a pupa of Chrysopa nigricornis. 



An examination of the tracheation of the wings of a pupa of 

 Chrysopa nigricornis reveals the nature of the two serial veins M' 

 and Cui' (Fig. 341). 



In order to show more definitely the composition of the two serial 

 veins, a diagram of an adult wing is given (Fig. 342). in which the 

 elements of the coalesced veins are represented slightly separated, 

 and the cross-veins connecting the coalesced veins are represented 

 by dotted lines. By comparing this diagramwith Figiire 340 the 

 homologies of the different veins can be recognized. 



The larvce of the lacewing-fiies are known as aphis-lions, because 

 they feed upon aphids; they are found on the foliage of plants in- 

 fested by these pests; they also feed upon other small insects and 

 the eggs' of insects; they are spindle-shaped (Fig. 339) and arefur- 

 nished with piercing and sucking mouth-parts like those of ant-lions. 



Nearly all aphis-lions are naked; but a few species cover them- 

 selves with the skins of their victims and other debris, as do the larvs 

 of Hemerobius. This has l^een obser^'ed by European writers (Sharp 



