536 
Annual Report of New York 
Having found such a situation as it requires the larva determines in 
what position it will place itself to remain during its pupa state, for 
there is much diversity in our white butterfly in this respect, it being 
sometimes suspended upon the underside of a horizontal or an inclined 
surface, and at other times against the side of a vertical surface; and 
•it is held in a variety of positions, horizontal, oblique, or almost per¬ 
pendicularly upward or downward, usually with its back but some¬ 
times with its right or its left side downward. 
Having selected the spot it will occupy and the position in which 
it will suspend itself, it requires a loop to be made around its body to 
hold it in this position. To give its feet the secure foothold they 
will require while this loop is constructing it first spreads a slight 
carpeting of silk threads upon the surface on which it is to stand, 
forming also at its lower end a thick mass or little hillock of these 
threads. It then fastens the hooks of its hind feet securely into this 
mass of threads, aud clinging to the carpeted surface with its middle 
legs, its body is so very soft and flexible that it is able to bend and 
turn its head backward touching either side or the top of the back at 
a point one-third of the distance from the hind to the fore end. And 
with its head thus turned backward it fastens to the surface at one 
side of its body a thread of silk which it spins from its mouth. It 
then carries its head up over its back and down upon the opposite 
side of the body, where the mouth fastens the other end of the thread, 
thus forming a loop around its body holding it to the surface on which 
it is standing. This single thread, however, is exceeding fine and 
possessed of but little strength. The worm therefore carries its 
mouth back again by the same route, to the opposite side, thus spin¬ 
ning a second thread, with its end fastened at the same point where the 
first one was commenced. And it thus continues to move its mouth 
from one side to the other, until it has formed a skein of threads of 
sufficient size and strength to securely sustain the weight of its body. 
Reaumur states the number of threads in the loop to be about fifty. 
But in our American species there is no uniformity in this loop, it 
being in some instances not a fourth the size that it is in others. If 
the larva gains some secluded corner where it will experience no 
molestation, it does not trouble itself to spin but a few threads to 
form this loop. 
I he most laborious part of this work, and that which occupies the 
principal part of the time that this loop is being constructed, is the 
fastening of the ends of the threads to the surface on each side of the 
Worm. As the tension upon the threads is almost directly upward 
