78 Indian Museum Notes. [Vol. II. 



the Indian Museum in May 1890, and produced, in the early part o£ the 

 rains, a female moth of the typical pinkish color, and Mr. Knyvett also 

 writes that he has found A. roylei cocoons on Mohwa trees, oak, and 

 birch in Sikkim. The above is all that we at present know about A. 

 roylei proper. The figures of the caterpillar and cocoon are taken from 

 specimens obtained by Mr. A. V. Knyvett in Sikkim ; those of the moths 

 from Hutton'stype specimens which are in the Indian Museum collection. 

 Closely connected with A. roylei proper is an insect with a firm singled- 

 walled pedunculate cocoon which has been found by Mr. A. V. Knyvett 

 upon wild cherry trees in Sikkim. The cocoons of this form, which have 

 been sent to the Indian Museum, are much like the cocoons of Anthercea 

 frithii, but moths reared from them by Mr. Knyvett are almost indistin- 

 guishable from moths reared from the typical double- walled cocoons of 

 A. roylei, the chief distinction consisting in the greater pinkness of those 

 reared from the pedunculate cocoons. As, however, the females reared 

 from double-walled cocoons show every variety of color from pink to 

 oreenish brown, and are in some cases altogether indistinguishable from 

 females reared from pedunculate cocoons, it would seem most probable 

 that the difference in the structure of the cocoon is to be attributed more 

 to the difference in the food plant than to any specific distinctness in the 

 insects. The differences observed by Mr. Knyvett between the caterpil- 

 lars of the two forms, though very remarkable, not being of a sufficiently 

 radical nature to warrant their separation under distinct specific names. 



Oak Silk Worms op China and Japan. Plate 7 ,fig. 2, and plate 8. 



An account of Anthercea roylei, which is the oak-feeding silk worm of 

 the Himalayas, would be incomplete without a notice of the very closely 

 allied oak-feeding silk worms of China and Japan. These are Anthercea 

 pernyi (Guerin Meneville, Rev. etMag. deZool. 1855, p. 297, pi. 6, fig. 1), 

 which is reared in a semi-domesticated state over large areas in Northern 

 China, for the production of silk, and Anthercea yamamai, which is 

 the corresponding form in Japan. About twenty-five years ago, when 

 mulberry silk raising in Europe was threatened with extinction, these 

 species attracted a good deal of attention, and were introduced 1 aud 

 partially acclimatized in France by experimentors, who hoped to furnish a 

 substitute for the mulberry-feeding species. The revival of the mul- 

 berry silk industry, however, with the adoption of Pasteur's treatment for 

 the silk worm disease, has thrown the oak-feeding species again into the 



1 As told by Van Westmaas (Tijd Voor. Ent. VII, 1864.), the story of the obtaining 

 of the eggs of A. yamamai, through a young Japanese, who in 1862 risked his life to get 

 them for M. Pompe van Meerdervoort in Japan, recalls the difficulties encountered in the 

 middle ages by the monks who first introduced the eggs of the mulberry -feeding species iuto 

 Europe from China. 



