I 82 TREATISE UPON THE 



the dampness of the air, which makes them hatch in rainy 

 weather. We do not find how many days are necessary 

 for the change or metamorphose of the chrysalides, and we 

 conclude, that there is no fixed time ; that it is advanced or 

 retarded without our being able to divine the cause; but it 

 is not common to wait more than eight or ten days, when 

 proper weather is chosen : that is to say, damp and warm 

 weather. If it be delayed a little longer, we will have the 

 gratification to see all the cocoons send forth their butter- 

 flies nearly at the same time. 



The butterfly of the wild silk worm, says P. D'ln- 

 carville, has glassy wings, of the fifth class of phalenes, 

 according to the system of M. de Reaumur. It carries its 

 wings parallel to the superfices of its position, and leaves its 

 body entirely uncovered : its wings are no more extended 

 when it flies, than when at rest. This butterfly has scarcely 

 its wings dry, when it seeks to make use of them, and fly. 

 As persons are sure of drawing the males by means of the 

 females, the liberty of flying outside is left to them ; but the 

 females are taken, as soon as they come out of their cocoons, 

 and are attached with a thread of pretty long silk by one of 

 their wings, and the other end attached to a large dried 

 bundle, of a species of millet, suspended in the air, and 

 which the botanists call milium arundinaceum. The Chi- 

 nese by this plan obtain great advantages. The males 

 impregnate the females the first and the following nights, 

 though they sometimes disappear entirely during the day. 

 The females, which are tied to the bundle of millet, deposite 

 there their eggs after the second night, and continue to do 

 so about eight or ten days ; but towards the end they lay 

 much less. The entire laying is not less than four or five 

 hundred eggs. The heat of the season suffices to make the 



