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-cubitus~one or vein Cui', re- 

 spectively (Fig. 340, M' 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 Cu/ (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 diagram with Figure 340 the 

 homologies of the different veins can be recognized. 



The larvae of the lacewing-flies 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 are fur- 

 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 larvas 

 of Hemerobius. This has been observed by European writers (Sharp 



