[63]

Red Cabbage Cot

Oct. 19th Horizontal glass Did not sleep last night too old

Plant kept darkness yesterday now under brown paper cover

[data not transcribed]

(Used)

Have darkness or age checked movements

Cover removed for observation ─ from 2 few

I ought to observe whether in movement tomorrow manner length of stem & how much magnified

[63v]

72 84

Chap. 8 Insects.

In this class, the Lepidoptera alone afford the means of judging of the proportional numbers of the sexes; for they have been collected with special care by many good observers, and have been largely bred from the egg or caterpillar state. I had hoped that some breeders of silk-moths might have kept an exact record, but after writing to Frances and Italy, and consulting various Treatises, I cannot find that this has ever been done.

The general opinion appears to be that the sexes are nearly equal, but in Italy, as I hear from Prof. Canestrini many breeders are convinced that the females are produced in excess. The same naturalist, however, informs me that in the two yearly broods, produced by of the Ailanthus silk-moth (Bombyx cynthia) the males greatly preponderate in the first, whilst in the second the two sexes are nearly equal, or the females rather in excess.

In regard to Butterflies in a state of nature several observers have been much struck by the of apparently enormous preponderance of the males in many cases 56. Thus Mr. Bates 57 *(T) in speaking of the species, no less than about a hundred in number, which inhabit the Upper

[Descent 1: 309: "In this class, the Lepidoptera alone afford the means of judging of the proportional numbers of the sexes; for they have been collected with special care by many good observers, and have been largely bred from the egg or caterpillar state. I had hoped that some breeders of silk-moths might have kept an exact record, but after writing to France and Italy, and consulting various treatises, I cannot find that this has ever been done. The general opinion appears to be that the sexes are nearly equal, but in Italy as I hear from Professor Canestrini, many breeders are convinced that the females are produced in excess. The same naturalist, however, informs me, that in the two yearly broods of the Ailanthus silk-moth (Bombyx cynthia), the males greatly preponderate in the first, whilst in the second the two sexes are nearly equal, or the females rather in excess.
In regard to Butterflies in a state of nature, several observers have been much struck by the apparently enormous preponderance of the males.56 Thus Mr. Bates,57 in speaking of the species, no less than about a hundred in number, which inhabit the Upper Amazons, says that the males are much more numerous than the females, even in the proportion of a hundred to one."]