BY U. J. TILLYARl). 257 



submerged. One can often gather a stem or le.if of water-weed 

 punctured all over by this common insect, and a little careful 

 observation will show the colourless transparent eggs in the tissue. 



Since I wrote the paper referred to, 1 have been able to obtain 

 many useful works of reference on Odonata which I lacked 

 before, and from which it is clear that the general habits of the 

 genus Lestes, with one or two exceptions, are the same the world 

 over. With the detailed knowledge contained in the works of 

 de Selys and others, it would have been impossible to have com- 

 mitted the error I did. I have therefore studied carefully all 

 the information I have been able to obtain concerning the 

 known life-histories of species from other countries, before 

 venturing to publish any more of my own observations on 

 Australian species. 



Many species are exceedingly difficult to keep and breed out 

 in aquaria. They apparently do not take kindly to artificial 

 conditions. One has to be always on guard against their canni- 

 balistic propensities, and only a few nymphs of any of the larger 

 kinds can be kept with safety even in a large aquarium. Worst 

 of all is the apparent inability of the full-fed nymph, — in the 

 case of the Libellulidos and Gomphince — to climb out of the water 

 and undergo transformation. Only with the greatest difficulty 

 can they get up slanting twigs; and it is necessary, for success, to 

 give them a shelving bottom up which they can crawl to dry 

 land. Once out of the w^ater, they seem able to negotiate vertica 

 stems of grass or twigs with fair success, although they generally 

 prefer a clump of several stems together, or, in many cases, 

 remain on the ground to undergo the change. 



Breeding the nymph is after all only a small part of the study 

 of life-histories. More can be done by spending long days in the 

 S))ring and summer, watching the insects in their natural haunts. 

 Besides the method of oviposition, there is need to observe 

 carefully the methods adopted by the males to captuie the 

 females and hold them securely during the process of copulation. 

 In this act the accessory appendages of the male, and the head 

 and thorax of the female play a prominent part, and the exceed- 

 20 



