872 RADIAL AND ZYGOPTERID SECTORS, ikc, 



portant that tlie doubt concerning Neosticta should be cleared 

 up. 



Unfortunately, Neosticta is a rare genus, the larvse being onlv 

 obtainable from one locality, Heathcote, twentv-one miles soutli 

 of Sydney. These larva; are rock-dwellers, somewhat reseml)linf 

 those of Diphlehia, but much smaller, and possessing two jointed 

 caudal gills. They live in the deep pools of clear cold water in 

 Heathcote Ci'eek and the Woronora River, and are only to lie 

 got by hauling rocks out of these recesses. 



Thanks to the kindness and energy of Mr. F. W. Carpenter 

 M.A., Science Master at Sydney Grammar School, I was enabled 

 to obtain, in August last, five well-grown larvae of Neosticta 

 canesceris from Heathcote. Four of these were in excellent con- 

 dition for study, having only recently entered the last larval 

 instar. The fifth was more advanced, being, in point of fact, at 

 almost exactly the same stage as the one previously examined. 



A preliminary examination of one of the cut-off wings of this 

 last larva showed that it closely resembled the one studied and 

 figured in my previous paper (2, PI. xiii., fig. 4). The pigmenta- 

 tion was very dense, and there was the same appearance of Rs 

 descending from R as before. However, when this condition 

 was studied under strong transmitted light, it was at once seen 

 to be due to the cuticularisation of tfie wing-sheath, already 

 noticed by me in the case of Diphlebia(z, p. 227). There was no 

 sign of the presence of a trachea Rs at all. 



Turning then to the less advanced larva?, it was an agreeable 

 surprise to find that the dissected-off wir)gs were moderately 

 transparent, so that the tracheation could be easily followed out 

 in detail. All four wings of each of the four larvae were care- 

 fully studied. Of the sixteen, fourteen agreed exactly with the 

 results obtained for all other Agrionidxe, viz., R is simple and 

 unbranched, and Ms ari.ses fiom the main stem of M between 

 M2 and M.j. The other two wings (one being a right foi'ewing, 

 the other a right hindwing) showed a peculiar aberration, the 

 origin of M3 having become shifted on to Ms near its base. This 

 peculiarity at once struck me as being of the utmost importance 

 as evidence of the t.i"ue nature of bridges and oblique veins, and 



