CLASS INSECTS. 431 



the time comprised between these successive moultings con- 

 stitutes what the agriculturalists call the various ages of 

 these little animals. At the approach of each moulting they 

 become as if dormant, and cease to eat; but after having 

 changed their skins their hunger redoubles. They call petite 

 freze the moment of the great appetite which precedes each 

 of the first four moultings, and grande freze that which is 

 observed during the fifth age of the worm. The quantity of 

 nourishment which they consume increases rapidly. It is 

 reckoned that for the larvae springing from an ounce of seed, 

 seven pounds of leaves are required during the first age, the 

 duration of which is five days ; twenty-one pounds during 

 the second age, which continues only four days; seventy 

 pounds for the third age, which lasts seven days; two hundred 

 and ten pounds during the fourth age, which continues seven 

 days ; and from twelve to thirteen hundred pounds during 

 the fifth age. It is on the sixth day of the last age that the 

 grande freze takes place. The worms devour then from two 

 to three hundred pounds of leaves, and cause, whilst eating, a 

 noise like a heavy shower of rain. The second day they 

 cease to eat, and prepare themselves to undergo the first 

 metamorphosis. They may be seen then to climb the branches 

 of small faggots placed intentionally and carefully above the 

 hurdles in which they had hitherto remained. Their bodies 

 become soft, and there springs from their mouth a thread of 

 silk which they draw after them. Soon they fix themselves, 

 throwing around them a multitude of threads of extreme 

 fineness, called bane or banne, and, suspended in the middle 

 of this network, spin their cocoon, which they construct by 

 continually turning on themselves in different ways, and thus 

 rolling around their body the thread which leaves the winder 

 with which their lip is pierced. The thread thus formed is 

 produced by glands which have much analogy with the 

 salivary glands of other animals, and the matter of which 

 it is composed is soft and viscous at the moment of its leaving 

 the mouth, but soon hardens in the air. From this it results 

 that the different turns of this single thread become agglu- 

 tinated together, and form an envelope whose tissue is firm, 

 and whose shape is ovoid. The colour of this silk varies ; 

 sometimes it is yellow, sometimes pure white, according to 

 the variety of the worm which has produced it, and the 

 length of each thread often exceeds six hundred metres, 

 (somewhat more than six hundred yards), but it varies much, 



