288 



STUDIES IN AUSTRALIAN NEUROPTERA, iv., 



Phylogenetically (if we may take the venation of the Mesozoic 

 fossils as a true guide), there can be little doubt that the most 

 archaic condition is that in which the costal space is not undulv 

 enlarged, and the costal cross-veins either slightly, or not at all, 

 branched, while the veins approaching all the rest of the wing- 

 border are freel\^ branched. Thus the costal space of the hind- 

 wing retains the archaic form, while the great enlargement of 

 the same space in the forewing, seen in such genera as Drepunep- 

 teri/x, together with the formation of the rectirrent costal veinlet 

 (Plate xiii., Cr) must be regarded as specialisations correlated 

 with increase in wing-breadth. 



(8). The fusion of M with R hasally in the forewiny, and the 

 fusion of M in the hindtving with the. weakly formed^ original^ 

 basal portion of Es. These are distinct specialisations in the 

 venation, which, though found in the Chrysopjidce and Dilaridoi 

 also, offer a definite distinction from the Ithonidce and Osmylidce, 

 where M is fused with R in both wings. 



(9). 'The unspecialised form of the antennae. These are formed 

 of very numerous, small joints, the basal joint being usually 

 slightly enlarged. The antenna; may be described as slender, 

 moniliform, and very finely pectinate. In length, they vary from 

 a little less than half the wing-length {Drepanepteryx), to about 

 the full length of the wing (Oxybiella). They most closel}' 

 resemble the antennae of Osmylidce (probably the most archaic 

 form of these organs), but these latter have the separate joints 

 longer and thinner by comparison. The antemise also serve to 

 distinguish the Hemerobiidoi from the Psychopsido', in which 

 these organs are exceedingly short; from the Chrysopidce, in 

 which they are exceedingly long; and from the Nymp)hida', in 

 which they are disiinctl}' thickened. 



(10). Position of rest: the wings completely hiding the body, 

 and placed almost vertically to the resting-plane, with the costal 

 margins downwards, the posterior margins meeting in a high 

 ridge above the body; the head bent downwards, and often partly 

 hidden by the projecting costse of the forewings. 



This resting-position is very like that of the Osmylidoi, and 

 C oiiiopterygidd', in both of which, however, the head shows much 



