THE EPHEMERA. 321 



Called the insects of a day. 



their perfect state all the species live |)Ut 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 insect^ 

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

 of the sun, being produced after sunset, during 

 the short nights of summer, and dying long be- 

 fore the dawn. All their enjoyments therefore 

 seem confined entirely to their larva state ; af 

 which time they scoop out dwellings in the banks 

 of rivers, which consist of small tubes made lifce 

 syphons, with two holes, the one serving for an 

 entrance, and the other as an outlet ; and these 

 are so numerous that the banks of some rivers 

 are observed to be full of them. When the wa- 

 ters decrease, they dig fresh hples lower down. 

 The flies are hatched nearly all at the same in- 

 stant, in such numbers as even to darken the air. 

 The females, by the help of the threads of their 

 tails, and the flapping of their wings, support 

 themselves on the surface of the water, and, in 

 an almost upright position, drop their eggs in lit- 

 tle clusters into the water. A single insect will 

 lay sometimes seven or eight hundred ; in some 

 places they multiply enormously, and are very 

 frequent about the waters. 



The singular quickness and ease with which 

 these little creatures strip themselves of the 

 slough of the nymph, in order to become flies, 

 is very surprising. We do not draw pur arm 

 more quickly from the sleeve of a coat, than the 



