264 STATES OF INSECTS. (Pupa.) 
as long and as sound as that of the seven sleepers, for the 
chance of viewing his predicted return of a comet, on 
stepping out of his cave: but ordinary mortals would 
consign themselves to the perils of so long a night with 
reluctance, apprehending a fate no better than what be- 
fel the magician, who ordered himself to be cut in small 
pieces and put in pickle, with the expectation of becom- 
ing young again. 
The duration, then, of an insect’s existence in the 
pupa state, depends upon its bulk, upon the temperature 
to which it is exposed, and upon a combination of these 
two circumstances. ‘This experiment appears very sim- 
ple. We seem to ourselves to have accomplished what is 
so often undertaken in vain—to have found an entrance 
into the cabinet of Nature, and to have made ourselves 
masters of the contents of one of the pages of her sealed 
and secret book. We deceive ourselves, however: this 
book, when it seems most legible, is often interlined with 
sympathetic inks, if I may so speak, which require tests 
unknown to us for their detection. If you lay up a con- 
siderable number of the pupze of a moth now called Lrio- 
gaster lanestris, the larva of which is not uncommon in 
June on the black-thorn, selected precisely of the same 
size, and exposed to exactly the same temperature, the 
greater number of them will disclose the perfect insect 
in the February following ; some not till the February of 
the year ensuing, and the remainder not before the same 
month in the third year®. Mr. Jones of Chelsea, a most 
4 This is a legend of Virgil, of which an account is given in The 
Lay of the Last Minstrel, Note xv. 12mo. Ed. 1822, p. 257. 
> Haworth Lepidopt. Britann. 1. 125. An instance is recorded in 
Scriba’s Journal, in which a pupa was not disclosed until the fourth 
year, B. i. st. ili, 222. Pezold. 170. 
