330 NATURALIST'S CABINET. 



The ephemerae or day-flies. 



This generally so disengages itself from the skin 

 of the chrysalis that it leaves it in exactly its 

 former appearance on the stem. At the first ex- 

 clusion of the insect the wings are weak and ten- 

 der, and folded into a very narrow compass. 

 During their unfolding, and till they become 

 perfectly dry, it continues almost motionless ; but 

 they are no sooner completed than the little ani- 

 mal commences an inhabitant of the air, and 

 would now be as effectually destroyed by conti- 

 nual submersion under water, as the larva would 

 before have been by exposure to the air. 



The ephemera? or day flies, differ in many re- 

 spects from all other insects. Their larva} live 

 in water (where earth and clay seem to be their 

 only nourishment) for three years, the time they 

 consume in preparing for their cbange, 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 fur- 

 nished with wings, which 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 be- 

 comes a perfect ephemera, the mouth of which 

 has no jaws, but is furnished with four very short 

 thread-shaped feelers. The antenna? are short 

 and thread-shaped; and above the eyes, there 

 are two or three large stemmata. The wings are 

 erect (the lower ones much the shortest) and the 

 tail is terminated by long hairs or bristles. In 

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