70 SILKWORMS. 



age in the occupants of the same tray, so that all may moult at 

 the same time ; second, no intermission in the supply of food, 

 except during the moulting sicknesses ; third, plenty of room; fourth, 

 good ventilation, and a plentiful supply of fresh, dry air, at a 

 uniform temperature, especially during the fourth and fifth ages ; 

 and lastly, cleanliness, which becomes of increasing importance 

 with the advancing age of the larvae. But even if all these con- 

 ditions are strictly fulfilled, the silkworm rearer must be prepared 

 for disappointments, and must not expect to bring all his brood 

 successfully to their perfect state. There are many causes of loss 

 and imperfection, and it is to these that we must now turn. 



A little difficulty is occasionally experienced by the insect, even 

 in making its exit from the egg. Sometimes the hole through 

 which it is to escape is not quite large enough to allow the passage 

 of the head, and the young caterpillar is induced to try entering 

 the world stern foremost. This is a stupid proceeding, because 

 of course the head will have to come thiough sooner or later, if 

 the egg is to be really and effectively hatched. When all the body 

 has issued, then comes the attempt, of course a futile one, to 

 drag the large head through, and the creature becomes stuck in 

 that position, wearing the old eggshell as a bonnet, and necessarily 

 becoming soon starved to death. 



But one of the commonest sources of loss will be the moulting 

 sicknesses. Changing the skin, especially at the last two moults, 

 seems to be a very trying operation, and in a large brood there 

 are sure to be some who will succumb to the severity of the trial. 

 Such are called luzettes. There is no remedy for this disaster, 

 and the luzettes must simply be left to their fate, and removed as 

 soon as it becomes evident that they will not spin : for they will 

 speedily die, and their corpses will contaminate the air. If a 

 caterpillar receives a wound, the scab formed on its healing will 

 more or less interfere with the next moult ; the old skin will adhere 

 at the spot, and the insect, unless it receives external help, will 

 either be unable to remove it beyond that point, or will at least 

 be considerably inconvenienced by it, and will probably either die 

 or become more or less of a cripple. 



Unwholesome or too juicy food produces diarrhoea, the remedy 

 for which is, of course, the substitution of a more solid diet. Too 

 great heat, again, renders the worms feeble and sickly ; and some- 

 times they become yellow and limp, and soon die of a sort of 

 jaundice, called grasserie. Sometimes, again, a larva just manages 

 to get through its moult, but exhausts all its energy in the process, 

 and has not enough left to recommence eating, and therefore 

 perishes. Such are called arpians. 



