The Zoologist— July, 1871. 2689 



"Notes on the Practical System folloioed in the Province of Shang-tung 

 for the cultivation of Bomhyx Pernyi. 



" Five or six years (according to their growth) after the oaks have been 

 planted, each trunk is cut off close to the roots about November, and in the 

 following year, the new branches springing out round the foot, the truncated 

 trees -will form into low bushes. The first year after the oaks have been 

 cut, the second yearly production of cocoons can only be raised on them, and 

 they are afterwards used alternately with others for the consecutive 

 cultivation of the first and second yearly productions. In exjDlanation of 

 the above, let us suppose we have one hundred oak trees. These must be 

 divided into two sections ; each section to be cut separately at the interval 

 of one year. Thus, out of one hundred trees, fifty, cut in November 1870, 

 will serve for raising the second yearly production of cocoons in August, 

 1871, and the first yearly production in May, 1872; while the other fifty 

 trees, cut in November, 1871, will serve for the second yearly production 

 in August, 1872, and the first yearly production in May, 1873. Once this 

 system is established, it is followed up by recutting every year that section 

 of the bushes which has already served for two successive productions of 

 cocoons within two years. When the second production of one section takes 

 place in the spring, the recutting is effected in July, directly after the 

 cocoons are gathered ; and when it occurs in August the recutting is done 

 in November. In this way both sections are used alternately every year for 

 each production of cocoons, allowing also ample time for the requisite 

 growth of the bushes. 



" The cocoons retained for obtaining seed must be kept during the winter 

 at a uniform cold temperature, taking care not to expose them to any heat 

 above 60° Fahrt. 



" On arrival of the spring, whenever the oaks begin to bud, the cocoons 

 intended for preparation of seed are strung together with thread, in long 

 rows, and suspended in rooms. Care must be taken, in order to facilitate 

 the issue of moths, that the point of suspension of each cocoon must be the 

 same that served to attach it to the leaf-stalk while in course of formation. 

 If the temperature at this time is not sufiiciently high for the development 

 of the chrysalis, it must be gradually raised artificially until the moths begin 

 to issue from the cocoons. When the moths are out it is necessary to wait 

 till they have well distended their wings before placing them in the coupling- 

 baskets. Coupling-baskets are lined on the inside with paper pasted all 

 round the sides and bottom, with the exception of the cover, to allow 

 ventilation. The same number of male and female moths are to be placed 

 in the baskets, with sufficient room for free movement. The moths generally 

 issue from the cocoons between 6 and 7 p. m., and their coupling, which 

 takes place directly afterwards, lasts about twenty-two hours. The male 



