85 [ 175 3 



Sixth day of the third age. 

 (Fifteenth of the rearing of the silkworm.) 



On this day the silkworms begin to rouse, and thus accomplish the 

 third age. 



The general view of this age presents the following result: In six 

 days the silkworm goes through its third age. In this age, those 

 worms proceeding from five ounces of eggs, have consumed nearly 

 300 pounds of leaves and young shoots. 



The muzzle of the silkworm during the third age, has maintained 

 a reddish ash color, and is no longer shining and black, as it appears 

 in the two first ages, but it is lengthened and more prominent. The 

 head and body are much enlarged since the casting of the skin, even 

 before they have eaten at all: proving that they were straitened in 

 the skin they have cast, and being now unconfined, the air alone has 

 expanded their bulk. This growth, which is considerable, is more 

 visible in this age than in the preceding. 



When this age is completed, the body of the silkworm is more 

 wrinkled, particularly about the head; they are of a yellowish white, 

 or rather fawn color, and to the naked eye they have no appearance 

 of hairiness. In this third age, we first hear, when the worms are 

 fed, a little hissing noise, similar to that of green wood burning. This 

 noise does not proceed from the action of the jaws, but from the mo- 

 tion of the feet, which they are continually moving: this noise is such, 

 that, in a large laboratory, it sounds like a soft shower of rain; by de- 

 grees, when the worms fasten to their food, the noise ceases. The 

 average length of the silkworms, which was six lines after the second 

 moulting, is become, in less than seven days, above twelve lines. The 

 weight of the insect has increased fourfold in the same period. 



It has been suSicient, during this age, to open the ventilator, the 

 door, and even the windows, when the weather was still and fine, so 

 as to lower the temperature by a degree only. In damp, close days, 

 a small wood fire, in the fire-place, renews the air, by drawing a cur- 

 rent, without injuring the interior atmosphere. During this age, it 

 never happened that the exterior temperature, although higher than 

 the interior, went beyond the prescribed limits. 



4. REARING OP THF SILKWORM IN THE FOURTH AGE. 



In this age, the worms proceeding from five ounces of eggs, sliould 

 occupy a space of about 412 square feet; the temperature should be 

 from 68° to 71°. In this fourth age, as in the fifth, there will proba- 

 bly be days in which it will not be possible to maintain the tempera- 

 ture of 71°, because of the heat of the weather as the season advances; 

 and in spite of artificial means it may very probably rise to 73° or up- 

 \vards. 



This augmentation of temperature does no harm. It is sufficient 

 that the circulation of air be not interrupted. The inoment it is {jei- 



