266 PREDACIOUS AND PARASITIC 



The fly is small and does not readily attract attention ; indeed, 

 it may easily be taken as it is found among a group of Aphides, for 

 some large species of that family, a resemblance which is 

 increased by the dusting of the body with a white mealy powder. 

 Once noticed, however, this character — combined with their pecu- 

 liar neuropterous wing venation and shape and the thread-like 

 antennae — make their identification easy. The front wings are 

 more irregular in shape than in the families already mentioned 

 (which approach the typical form), and are almost destitute of the 

 transverse veins which form so striking a feature in Chrysopa and 

 Hemerobius. The longitudinal veins, however, represent very 

 nearly the chief lines of venation in the former, as will be seen 

 when the drawing, now given, of the wings of Coniopteryx is com- 

 pared with an enlarged drawing of the wing of Chrysopa, which 

 will be given in the next part. By a comparison of these it seems 

 almost possible to see how the single longitudinal veins of the 

 humbler, although no doubt the more ancient family have given 

 rise to the elegant network which fixes our admiration in the deli- 

 cate ' Lacewing/ in which, as we shall see hereafter, the firm veins 

 of the former have given place to the fragile vascular structure 

 which supports the latter, and which is provided with a system of 

 circulation of a most marvellous character. 



The posterior wings of Coniopteryx differ far more from the 

 front wings, both in size and shape, than is the case with other 

 aphis-eating species, but the venation, so far as it persists, follows 

 the same plan as in the front wings. The shape of the hinder 

 wings, with their often narrowed extremities, approaches somewhat 

 that of the same structures in some species of the Hymenoptera. 

 The peculiar character of the venation possesses special interest 

 for the student of the development of species, as its comparatively 

 rudimentary structure suggests the possibility of a survival of the 

 details of an early stage in the growth of the neuropterous group. 



These insects were observed by Westwood to differ from the 

 typical species Hemerobius, in the slight reticulation of the wings, 

 the slight mealy covering without any appearance of cilia upon the 

 wings, the large size of the terminal joint of labial palpi, obsolete 

 ligula, absence of tibial spurs, and smaller size of posterior wings. 

 In common with other of the HemerobiincB they sit with wings 



