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Annual Report of New York 
observe how dexterously as soon as these pincers are drawn out from 
the mass of old skin they pass back over this mass, and then bending 
inward vigorously push the mass forward and briskly feel around its 
farther side, till they tind the little hillock of threads and instantly 
grasp it firmly. But the crumpled mass of skin and hairs crowds 
against and discommodes the hind part of the body. And how can 
the pupa relieve itself from this discomfort, having no mouth, no 
feet, wherewith to dislodge the mass and move it aside ? The 
expedient to which it resorts is most singular and admirable. 
Immediately as the curved tip fastens to the little hillock of 
silken threads a brisk circular motion of the body commences, like 
that of a pestle carried around and around in a mortar; not a semi¬ 
circular motion, as some authors have stated. Hereby the old skin 
is pressed against at every turn and is gradually broken from its 
attachments and finally drops to the ground. 
The change now described takes place with great rapidity. Reau- 
mur terms it the affair of a moment. From the opening of the skin on 
the back of the neck till the detachment and fall of the crumpled mass 
of old skin, it has been five minutes, in two instances in which I have 
noticed the time. 
It will be observed by those who are versed in what has been pub¬ 
lished on this subject, that my recital of the manner in which the 
pupa releases the hind part of its body, from the larva skin is quite 
different from that of Reaumur, our principal authority on this sub¬ 
ject hitherto. The observations of this distinguished philosopher and 
naturalist are so accurate and he describes them with such clearness 
that they have justly been universally confided in. And probably 
no one since his day has investigated this metamorphosis of the turnip 
butterfly, from deeming his history of it to comprise all the facts 
and to be perfectly authentic. 
According to Reaumur’s account, when the larva skin has been 
pushed back so far as to cover only about one-third of the length of 
the pupa, the insect ceases to shorten and lengthen itself, it being 
more convenient for it to directly withdraw the extremity of the 
pupa, and then push it back along the outside of the empty larva 
skin till it reaches the little cone or hillock of silk threads, into which 
it fixes the minute hooks at the extremity of the tail. We have 
already seen it is the habit of the larva when molting to draw the 
hind part of its body out of the old skin, in much the same manner 
that is stated of the pupa, accomplishing this by means of its three 
anterior pairs of feet. But the pupa having no feet or other external 
