STATES OF INSECTS. (Pupa.) 259 
pearance in some odtected pupe that the terms Chrysalis 
and Aurelia were applied to the whole. ‘The alchemists 
mistook this for real gold; and referred to the case as 
an argument in favour of the transmutation of metals. 
But Reaumur has satisfactorily shown, that in this in- 
stance the old proverb is strictly applicable—* All is 
not gold that glitters.” He found that this appearance 
is owing to the shining white membrane immediately be- 
low the outer skin, which being of a transparent yellow 
gives a golden tinge to the former; in the same way 
that tinfoil, when covered with a yellow varnish, as- 
sumes the metallic appearance which we see in gilt 
leather. He mentions, too, that for the production of 
this effect—it is essential that the inner membrane be 
moist: whence may be explained the disappearance of 
the gilding as soon as the butterfly is ready to escape 
from the pupa. The shade of colour in these gilded 
chrysalises is various: some are of a rich yellow, like 
pure gold; others much paler; and some nearly as 
white as silver. That of Brassolis Cassie is red with 
silver spots*. 
Though by far the greater number of the chrysalises 
of moths are of an uniform chestnut, brown, or black,— 
a few are of other colours; as that of Geometra alniaria, 
which is of a glaucous blue; of Catocala sponsa, lilac; 
and of C. pacta, of a lovely blue, caused by a kind of 
bloom, like that of a plum, spread upon a brown ground. 
A similar bloom is found on that of Parnassius Apollo, 
* Ins. Surinam. t. xxxii. Lister imitated the gilding of Chrysalises 
by putting a small piece of a black gall in a strong decoction of net- . 
tles: this produced a scum, which when left on cup-paper, he says 
will exquisitely gild it.—Ray’s Letters, 87. 90. 
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