666 



ON SOME EXPERIMENTS WITH DRAGONFLY 



LARV^. 



Bv R. J. TiLLYARD, M.A., F.E.S. 



During the past few years I have kept and reared a large 

 number of dragonfly larvae of various species. The present paper 

 is an attempt to collect together, in the form of a short narrative, 

 the notes I have made about them concerning three points only, 

 viz.: — longevity, resistance to starvation, and resistance to 

 drought. The chief experiments carried out were made with (1) 

 an unknown Libellulid larva of very peculiar structure, (2) a 

 number of larvae of Synthemis eu&talacia Burui. I shall deal 

 with these separately. 



i. The unknown Lihellidid larva. 



On October 10th, 1908, I dredged from tlie loose trash (con- 

 sisting mainly of half-decayed vegetable matter such as eucalypt 

 leaves) which collects in the small pools of the Heathcote Creek 

 (Illawarra district, N.S.W.), a large number of larvse of Austro- 

 gomphus ochraceus Selys. Together with these, I found twa 

 remarkable larvse of Libellulid form, which I am quite unable to 

 recognise as belonging to an}' known species. They are very 

 hard, and when touched, curl up into a half-ball, remaining 

 motionless for a considerable time. They have very short legs, a 

 somewhat triangular head, a broadly oval body absolutely flat on 

 the underside, and a deeply and very irregularly indented labium. 

 At the time I took them, I was already acquainted witli the 

 larvae of every dragonfly occurring in the neighbourhood, except 

 that of Synthemis Jlavoterminata Martin, so that it was not un- 

 reasonable to expect that this was the larva of that species. 

 However, I have since taken, and bred out, the larva of S. 

 Jlavoterminata, which is of an absolutely different type to the one 



