271 



either a complete or incomplete series of medio-cubitals. In 

 the hindwing, the anal fan is devoid of cross-veins, and there 

 is always either a complete or incomplete fusion of the pos- 

 terior branch of M with Cu^ the basal piece of M 3 + 4 

 descending transversely on to Cu x and appearing like a 

 cross-vein. In the hindwing also, Rs and M are fused basally 

 for some distance, as in most Perlaria. 



The Leptoperlidae are all slenderly-built insects. In the 

 position of rest, the wings are rolled round the body, the 

 left forewing overlying the right. The larvae, none of which 

 have so far been described, cling to rocks in running streams, 



and are remarkable for possess- 

 ing a unique development of a 

 rosette of gill-filaments around 

 the anus, numbering fifty or 

 more, which can be extruded 

 or withdrawn as required. 

 These gills are usually of a 

 beautiful pink or lavender 

 colour, more rarely whitish. 



No study has yet been 

 made of the tracheation of the 

 larval wing in this family. 

 While I was living at Hornsby, 

 New South Wales, I discovered 

 a small Leptoperlid larva on 

 the rocks in one of the creeks 

 flowing into Old Man's Valley, 

 and succeeded in rearing the 

 insect, which was found to be 

 a new species of Dinotoperla, 

 and will be described in this 

 paper. A study of the wing- 

 tracheation of this larva led 

 to the discovery of the presence 

 of the important specialization 

 mentioned above for the hind- 

 wing, viz., that there is always- 

 either a complete or partial 

 fusion of M 3 + 4 with Cu 1 . The 

 chief purpose of this short 

 paper is to demonstrate this 

 point, as a preliminary to the 

 complete working out of the 

 numerous undescribed genera 

 and species of this family 



Text-fig. 1. 

 Dinotoperla carpenteri, n. 

 (x8). 



The insect in the natural 

 position of rest. 



sp, 



