Note 588 — LETTER XXXI.
Reading edition
The caterpillar consists of twelve segments (Lyonnet t. i. f. 4, 5), excluding the head; on each of which, except the 2d, 3d, and 12th, there is a pair of spiracles. The chrysalis usually exhibits an analogy to this structure, though the first, second, and last pair of spiracles are more or less obsolete in most.