138 EPHEMERIDiE. — LIBELLULIDvE. 



Ephemeridae— Day-flies. 



Tlic name of Ephcmeridic has been given to the insects, 

 so called, in consequence of the short duration of their lives, 

 when they liave acquired their final form. There are some 

 of them which never see the sun ; they are born after it is set, 

 and die before it reappears on the horizon. 



These insects, indifferently called also Day-flies and May- 

 flies, usually make their appearance in the districts watered 

 by the Seine and the Marne, in the month of August; and 

 in such countless myriads, that the fishermen of these rivers 

 believe they are showered down from heaven, and accordingly 

 call the living cloud of them manna — manna for fish, not 

 men. Reaumur once saw them descend in this region so 

 fast, that the step on which he stood by the river's bank was 

 covered by a layer four inches thick in a few minutes. He 

 compares their falling to that of snow with the largest 

 flakes.^ 



Scopoli assures us that such swarms are produced every 

 season in the neighborhood of some particular spots in the 

 Duchy of Caruiola, that the countrymen think they obtain 

 but a small portion, unless every farmer can carry off about 

 twenty cartloads of them into his fields for the purpose of a 

 manure.^ 



Libellulidse — Dragon-flies. 



On account of the long and slender body, peculiar to the 

 insects of this family, they are with us sometimes called 

 DeviVs Darning-needles, but more commonly Dragon-flies. 

 In Scotland they are known by the name of Flying Adders, 

 for the same reason. The English, from an erroneous belief 

 that they sting horses, call them Horse-slingers. In France, 

 from their light and airy motions, and brilliant, variegated 

 dress, they are called Demoiselles ; and in Germany, for the 

 same reason, and that they hover over, and lived during 



1 Memoirs, vi. 485. Quot. by K. and S. Introd., i. 284. Cuv. An. 

 Kingd. — Ins., ii. 315. Ins. Trans., p. 373. 

 » Quot. by Shaw, ZooL, vi. 250. 



