1897'^ 



MICROSCOPICAL JOURNAL. 



249 



or the alkaline antiseptic tablet of Dr. Carl Seller, one 

 dissolved in a teacup, half full of warm water. — Medical 

 Fortnightly. 



On Rearing Dragonflies, 



By JAMES G. NEEDHAM, 



ITHACA, N. Y. 



Field work in Entomology is full of deliglitfnl oppor- 

 tunities, and none is more inviting, none more sure to 

 yield discoveries of scientific value, than work upon the 

 life-histories of Dragonflies. 



The nymphs which are aquatic, 

 have an interesting distribution in 

 depth. Those of Agrionidae and 

 of most Aeschinidae cling to the 

 floating or submerged vegetation. 

 These at least every aquatic collec- 

 tor has seen. Those of Libellulidae 

 sprawl upon the bottom amid fal- 

 len trash. Those of Gomphinae 

 burrow shallowly along beneath the 

 film of sediment that lies on the 

 bottom, with the end t>f the abdo- 

 men turned up for respiration. 



It is very easy to collect them. A garden rake with 

 which to draw ashore the stuff to which they cling and a 

 pail of water in which to carry tliem home is all the 

 aj[>j)aratus desirable in spring. Later when a new 

 growth of weeds is rooted fast to the bottom, the rake 

 will have to be exchanged for a wtiter-net. Withdrawn 

 from the water, the nymplis 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 to yield the best collecting are 



