DISEASES OF INSECTS. 213 



progress, it is best to burn or bury them, since if the 

 poultry pick them up they might be poisoned by them. 

 A third disease of silkworms is called Les Moris Blancs, 

 or Tripes, which is also occasioned by impure air, when 

 the leaves the animal feeds upon are heaped so as to 

 produce fermentation. The caterpillars attacked by it 

 die suddenly, and preserve after their death the sem- 

 blance of life and health. Too great heat, whether ar- 

 tificial or natural, occasions La Tott/fe, a fourth, which, 

 when the heat continues long, destroys all those that 

 are arrived at their last stage of existence in their larva 

 state. Black points scattered over different parts of the 

 body, or livid and blackish spots in the vicinity of the 

 spiracles, followed by a yellowish or reddish tint, are 

 symptoms of a fifth malady, called La Muscardine. 

 After this the animal soon dies, and becomes mouldy, 

 but does not stink. This disease is not contagious, and 

 is thought to be caused by a moist heat, attended by 

 pernicious exhalations. La Luzette, Luisette, or Clairene, 

 is another malady, which shows itself most commonly 

 after the fourth moult. It seems to arise from some 

 original defect in the egg. The caterpillars attacked by 

 it may be known by their clear red and afterwards dirty 

 white colour ; their body becomes transparent, and the 

 matter of silk exudes in drops from their spinnerets; 

 consequently, though as voracious as the rest, they are 

 never able to construct a cocoon, and should be de- 

 stroyed. Les Dragees is the name given to cocoons 

 which include a larva that never becomes a pupa. The 

 cause of this disorder has not been ascertained, and whole 

 broods are sometimes subject to it, which, as in the last, 

 seems to imply some defect in the eggs. But as the ca- 

 terpillar spins its cocoon, and the silk is as good as usual, 



