LEPIDOPTERA. 233 
to litters as thin and clean as possible, and there sleep ina good 
state of health. When the mass of worms is well awake again, the 
next thing to do is to take them off the litter on which they 
moulted and to give them food. If this problem were pro- 
posed to a person strange to the operation which is now occu- 
pying our attention—to separate the worms from the faded and 
withered food upon which they are reposing, without touching 
them,—he would certainly be very much at a loss what to 
answer.. The solution of this problem presented for a long time 
great difficulties, and occasioned numerous reverses in the rear- 
ing. Now-a-days, thanks to the employment of a net, the 
délitement, or taking them off their bed, has become an easy 
operation. 
Over the worms, placed on a table, is spread a net, the 
meshes of which are broad enough to allow them to pass through. 
On this net are spread the leaves which are to compose a meal. 






penis 211.—Lozenge-shaped net. Fig. 212.—Square net. 
The worms immediately leave the old food, and get on to the 
new leaves. They then lift the litter with the worms, and throw 
away the old leaves, now unoccupied, clean the table, and replace 
the net with the worms. At the next délitement the first net is 
found under the litter. Figs. 211 and 212 represent two forms of 
these nets made of thread. 
Thread nets, which were of great use, have been supplanted 
lately, with great advantage, by paper ones, which were invented 
