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THE EPHEMERA OR DAY-FLIES. 



THE Ephemerae differ in many respects from all 

 other insects. Their larva live in water (where earth 

 and clay seem to he their only nourishment) for three 

 t years, the time they consume in preparing for their 

 change, which is performed in a few moments. The 

 larva, when ready to quit that state, arises to the 

 surface of the water, and, getting instantaneously 

 rid of the skin, becomes a chrysalis. This chrysalis is 

 furnished with wings, w r hich it makes use of to fly 

 to the nearest tree or wall ; and, there settling, it in 

 the same moment quits a second skin and becomes 

 a perfect Ephemera. In this state all the species 

 live but a very short time, some of them scarcely 

 half an hour, having no other business to perform 

 than that of continuing the race. They are called 

 the insects of a day ; but very few of them ever see 

 the light of the sun, being produced alter sunset, 

 during the short nights of summer, and dying long 

 before the dawn. All their enjoyments therefore 

 seem confined entirely to their larva state. 



The Ephemerae are very frequent near waters, and 

 in some places multiply enormously. About Laz, in 

 Carniola, a province in Germany, we are informed, 

 by Scopoli, that they are so numerous in the month 

 of June that they are used as manure, and if each 

 farmer cannot obtain more than twenty cart loads, 

 the harvest is considered a bad one. 



The larvae scoop out dwellings in the banks of ri- 

 vers, which consist of small tubes made like syphons, 



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