WILD SILK WORMS. 181 



followed for the silk worms of the mulberry tree, which is 

 very likely, we have nothing to add to what has been said 

 in the Memoir on Mulberry Trees and Silk Worms. To 

 keep the cocoons more commodiously, they are strung to- 

 gether by their extremities, on a thread of silk, and several 

 strings are formed like beads. The sole precaution that is 

 necessary to preserve them, consists in suspending them in 

 a place where they will be sheltered from the north wind, 

 the rain, sun, and cold air. The Chinese do not disapprove 

 of their being housed ; but, to believe them, it is always 

 better to follow nature as nearly as possible ; and, the wild 

 silk worms, as every body knows, suspend their cocoons to 

 the trees on which they feed, without even seeking the most 

 sheltered places. 



It is much more difficult to make the wild silk worms 

 hatch than those of the mulberry tree: I have said to hatch 

 them, it would be better to say, to procure the metamorpho- 

 sis, for they hatch without any care. Father D'Incarville 

 failed in the first attempt ; the half of the Summer had 

 passed, though he had done his best, without obtaining a 

 butterfly. " I thought I was deceived," said he, in his 

 journal, " and that he (his agent) had given me cocoons in 

 which the chrysalides had perished." Upon which, disheart- 

 ened with this ill success, he shut them up in a drawer, 

 where he forgot them, and found them hatched in the month 

 of October, when he opened the fatal prison where he had 

 put them, and where they had miserably died. To make 

 these butterflies hatch, the cocoons must be strung and sus- 

 pended in a warm room, watered and dampened several 

 times during the day, in the warmest weather. There are 

 some who prefer to expose them to the vapor of a large 

 vessel of warm water, which is milder, and better imitates 



