BY R. J. TILLYARD. 669 



Meanwhile its colour darkened fioin a semi-transparent brown 

 to a dark opaque bIackish-l)rown, indicating the approach of an 

 ecdysis. On November .'3rd it changed its skin. I was fortunate 

 in seeing the change, wliich occurred in the earl}' morning and 

 took a considerable time — nearly an liour. The larva on emerging 

 from its skin was of a very pale green colour, but on my return 

 in the afternoon it was quite brown again. I do not know of any 

 other dragonfly larva in which the skin iiardeus and darkens so 

 quickly after ecdysis. 



I now had hopes that tins larva, alread3'more than a year old, 

 would emex'ge during the summer of 1909-10. But although it 

 was plentifully supplied with food, it seldom took a meal, and 

 grew very slowly. By the beginning of March it had settled 

 down again in its old position at the base of the stick, Though 

 it occasionally wanders about at night, it keeps in one position 

 during the day. To-day (June 11th, 1910) it is still quiescent. 

 As it is now nearly midwinter, it will evidently not emerge until 

 October or November, at tiie earliest. 



The conclusions I make from these observations are : — 



(1) As regards longevity. Dragonfly larvae of some species can, 

 and do, live for more than a year; under adverse conditions, they 

 can live more than two yeai's. Even supposing that the ovum 

 from which the larva X sprang was laid as late as February, 1908, 

 and hatched, say, in March, this larva is now two years and three 

 months old. And as it was already so far grown, when I took it 

 in October, 1908, as to possess small wing-cases, I do not think 

 we can possibly suppose that it was hatched later than March, 

 1908. 



(2) As regards resistance to starvation. The larva X certainly 

 had no food from January 2.")th, 1909, to September 29th of the 

 same year, i.e., for eight months; and probably it had gone without 

 food for a month previous to Januar}'^ 25th, during my absence 

 from .Sydney. 



(3) As regards resistance to drought. The larva X, taken from 

 a clear mountain-stream which is never dry, withstood a con- 

 siderable degree of drought for nine weeks. As I did not allow 



