512 THE CADEW FLIES. 



ahaped ; and above the ejes there are two or three large stemmata. 

 The wings are erect, (the lower ones much the shortest,) and the taii 

 is terminated by long hairs or bristles. 



The I^phemera9 differ in many respects from all other insects. Their 

 lan-(B live in water for three 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, rises to the surface of the water, and, 

 instantaneously freeing itself from its skin, becomes a chrysalis. This 

 chrysalis is furnished with wings : it flies to the nearest tree or wall, 

 and, there settling, it at 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 few of them ever see the light of the 

 sun ; being produced after 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 Ephemera are very frequent near waters, and in some places 

 they 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 larviB scoop out dwellings in the banks of rivers. These 

 consist of small tubes, made like 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 waters decrease, they dig fresh holes lower down. 

 The flies are produced nearly all at the same instant, and in such 

 numbers, as even to darken the air. 



The females, aided by 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 little clusters into the 

 water. A single insect will sometimes lay seven or eight hundred 

 eggs. 



OF THE PHRYGANE^, or CADEW FLIES. 



The mouth is furnished with a horny, short, curved mandible, and 

 four feelers. The antenn£e are setaceous, and longer than the thorax. 

 The wings are equal, and incumbent; and the lower ones are folded. 



The Phryganeae are to be observed, during the spring and summei 

 months, flying about, or resting upon the grass and weeds near the 

 borders of rivers, streams, and ponds. They deposit their eggs on 

 aquatic plants. These are enclosed in a glairy matter, as transparent 

 as water, and of the consistence of jelly, by means of which they 

 firmly adhere to the place where they have been deposited. 



Tne larvae, when hatched, form for themselves tubes of silk, the 

 'iLtei or of which is smooth and polished, and to the exterior of which 



