158 THE ENTOMOLOGIST. 



France, more than fifty years ago, a most terrible disease (which 

 has now, it is said, disappeared) was the * Muscardine ' (a white 

 vegetable parasite which was developed inside the worm or in 

 the chrysalis or pupa. Whilst the Muscardine preyed on the 

 mulberry silkworms, the other epidemics had disappeared ; but, 

 from 1845, two other distinct diseases made their appearance 

 one after the other. The first was the * Pebrine ' (pepper 

 disease), a very ancient affection of the worms, which when 

 attacked by it are covered with black spots, and grow smaller 

 and smaller till they die. Later on, a second, very distinct from 

 the first and a worse disease, made terrible ravages among the 

 worms ; this is the * Flacherie.' The Flacherie is worse than 

 the Pebrine, because, after all the expense and the labour of 

 rearing the worms, which eat and grow well, showing apparently 

 no signs whatever of disease, they die within a few days of the 

 spinning period : hence a great disappointment. These diseases 

 may co-exist, but when they are intense it often happens that 

 one excludes the other, according to the ordinary law of epi- 

 demics. These diseases, created by the overcrowding of worms 

 in hot rooms, may also be the consequence of rearing from eggs 

 containing the germ of disease ; for it must be remarked that a 

 certain number of diseased worms live and procreate in spite of 

 that germ of disease in them. On the contrary, silkworms 

 reared in the open air, on trees, and in suitable climates, are in 

 such conditions of ' hygiene ' as to be almost entirely protected 

 from contagious diseases." 



The rearing of the best wild silkworms, on a large scale, for 

 manufacturing purposes, should be encouraged in their native 

 countries ; for although the species previously mentioned, and 

 some others, might be acclimatized and even naturalized in 

 Europe, yet, they could not, as a rule, be bred in such quantities 

 as in their native countries. Besides, as these wild silkworms, 

 like other Lepidoptera, are reared in Europe by entomologists in 

 order to study the larvae and obtain fresh specimens of the 

 perfect insects for collections, it will also be a profitable occupa- 

 tion, to entomologists and other persons residing abroad, to rear 

 larvae of various species for the purpose of sending the pupae to 

 Europe, as they will always be readily purchased. 



With respect to the rearing of the larvae or caterpillars in 

 their native countries, the best plan is of course to rear them on 

 the trees or their other food-plants, taking care to protect them 

 against the attacks of birds or other enemies. Muslin bags or 

 sleeves may be used to cover the larvae ; but when silkworms are 

 reared on a large scale they have to be watched day and night 

 till they have formed their cocoons, as is done with the yama- 

 mdi in Japan. 



If recourse must be had to cut branches to rear the larvae, the 

 branches should be large instead of small, the stalks being of 



