94 



THE CANADIAN ENTOMOLOGIST. 



ON REARING DRAGONFLIES. 



BY JAMES G. NEEDHAM, ITHACA, N. Y. 



Field work in Entomology is full of delightful opportunities, and 

 none, just at present, is more inviting, none more certain to repay well 

 even a little effort, none more sure to yield discoveries of scientific value, 

 than work upon the life -histories of Dragonflies. 



Of the species occurring throughout the central tier of States, a 

 majority perhaps has now been bred ; but of the Canadian, far western 

 and southern species the known nymphs are few and far between. 



The nymphs (fig. 15), which are all aquatic, 

 have an interesting distribution in depth. Those 

 of Agriofiidae and of most Aeschnmae cling to 

 floating or submerged vegetation. These at least 

 every aquatic collector has seen. Those oi Libel- 

 lulidae sprawl upon the bottom amid fallen trash. 

 Those of Gomphinae burrow shallowly along be- 

 neath the film of sediment that lies on the bottom, 

 with the end of the abdomen turned up for respira- 

 tion. 



It is very easy to collect them, especially in 

 spring. A garden rake with which to draw ashore 

 the stuff to which they cling and a pail of water 

 in which to carry them home is all the apparatus 

 desirable at that season. Later, when a new 

 growth of weeds is rooted fast to the bottom, 

 the rake will have to be exchanged for a water-net. Withdrawn from the 

 water, the nymphs render themselves evident by their active efforts to get 

 back, and need only to be picked up. The number of species one will 

 find will generally depend on the variety of aquatic situations from which 

 he collects. The places apt to yield the best collecting are small perma- 

 nent pools, shallow inlets in the shores of lakes, and the places where the 

 trash falls in the eddies of streams. 



They are quite as easily reared. I have found common wooden kits 

 and pails half filled with water, with screen or netting covers, entirely 

 satisfactory. A number of nymphs, if near one size, may safely be kept 

 together (excepting only a few notoriously cannibalistic Aeschninas : e. g., 

 Afiax Junius), and if not grown may be fed upon such small insects as a 

 net will gather in any pond. A good square meal once a week will keep 



Fk;. 15. — Aeschnid nymph. 



