278 STUDIES IN AUSTRALIAN NEUROPTERA, iv., 



nor can we ever expect that the ancestry of any part of them is 

 preserved for us in fossils, except that of the semi-aquatic 

 Osmylidce and their nearest allies. As for the Hemerobiida', 

 essentially a forest-dwelling group, we should expect to find them 

 in Baltic amber (where several species do occur), but to look for 

 their ancestors in freshwater or estuarine deposits, such as those 

 at Solenhofen, is unreasonable, since they were neither aquatic, 

 semi-aquatic, nor strong-Hying, as far as we are able to judge. 



I conclude, therefore, that the Ithonidce are an exceedingly 

 archaic I'emnant of the old Neuropteroid stock, from which, later 

 on, the Dilaridce (with only two sectors) branched oiF, and whose 

 main stem is represented to-day in the more highly reduced 

 Hemerobiidce. Apart from these three families, all the rest of 

 the Neuroptera, with their single radial sector, must 1)6 con- 

 sidered as a more recent and highly specialised stock, of which 

 the Osmylidce and their near allies stand closest to the ancestral 

 form, and from which the Myrineleontida', A seal aphid ce, Chryso- 

 pidce, and Maittispidce arose, as the most vigorous and dominant 

 offshoots. 



The nearest relatives of the Ithonido' are undoubtedly the 

 Dilaridce (not found in Australia), which may be distinguished 

 by their smaller size, slenderer build, the strongly pectinate 

 antennee of the male, the presence of a lai'ge ovipositor in the 

 female; and, in the venation, the lack of strong ridging of R and 

 Cuj, the possession of only two radial sectors in the forewing, 

 and the presence of fewer unspecialised crossveins. 



Genus Ithone Newman. (Plate xii.). 



Newman, Ent. Mag., v., 1838, p.l81. 



Characters as given above for the family, with the following 

 additions : — No setse or fine hairs on any of the crossveins 

 except the costals. Foreteys placed close under the head, with 

 the coxae much enlarged and close together (Plate xii., tig.2). 

 Tibice of all legs with a pair of short spurs. Tarsi five-jointed, 

 the basal joint very long, a large bilobed empodiiom between tlie 

 claws. Anal appendages of male strongly forcipate. 



Genotype, Ithone /nsca Newman. 



