_Attacus (antheroea) roylei_ (with sixty cocoons); three pairings only
were obtained, and this species I found the most difficult to pair in
captivity. Two moths emerged on the 5th of March, a male and a female,
and a pairing was obtained; but the weather being then too cold, the ova
were not fertile, the female moth, after laying about two hundred eggs,
lived till the 22d of March, which is a very long time; this was owing
to the low temperature. The moths emerged afterward from the 8th of
April till the 25th of June. A pairing took place on the 2d of June, and
another on the 6th of June.

Roylei (the Himalaya oak silkworm) is very closely allied to Pernyi, the
Chinese oak silkworm; the Roylei moths are of a lighter color, but the
larvae of both species can hardly be distinguished from one another.
The principal difference between the two species is in the cocoon. The
Roylei cocoon is within a very large and tough envelope, while that of
Pernyi has no outer envelope at all. The larvae of Roylei I reared did
not thrive, and the small number I had only went to the fourth stage,
owing to several causes. I bred them under glass, in a green-house. A
certain number of the larvae were unable to cut the shell of the egg.

Here are a few notes I find in my book: Ova of Roylei commenced to hatch
on the 29th of June; second stage commenced on the 9th of July. The
larvae in the first two stages seemed to me similar to those of Pernyi,
as far as I could see. In second stage, the tubercles were of a
brilliant orange-red; on anal segment, blue dot on each side. Third
stage, four rows of orange-yellow tubercles, two blue dots on anal
segment, brilliant gold metallic spots at the base of the tubercles on
the back, and silver metallic spots at the base of the tubercles on the
sides. No further notes taken.