798 
ANNUAL REPORT OF NEW YORK 
OAK. LIU133. 
of the last year, all the remainder of the twig being the green succulent 
growth of the present year. She places her egg near the tip of this twig, in the 
angle whole one of the leaf-stalks branch off from it. The young worm 
which hatches therefrom sinks himself into the center of the twig and feeds 
upon the soft pulpy tissue around him until it is all consumed, leaving only 
the green outer bark, which is so thin and tender that it withers and dries 
up, and ere long becomes broken. By the time this green tender end of 
the twig is consumed the worm has acquired sufficient size and strength to 
attack the more solid woody portion forming its lower end. He accord¬ 
ingly cats his way downward in the centre of the twig, consuming the pith, 
to its base, and onward into the main liinh from which this twig grows, 
extending his burrow obliquely downward to the center of the limb, to a 
distance of half an inch or an inch below the point where the lateral twig 
is given off. 
The worm being about half grown, is now ready to cut the limb asunder. 
But this is a most nice and critical operation, requiring much skill and cal¬ 
culation ; for the limb must not break and fall whilst he is in the act 
of gnawing it apart, or he will be crushed by being at the point where it 
bends and tears asunder, or will fall from the cavity there when it breaks 
open and separates. To avoid such casualities, therefore, he must after 
severing it, have time to withdraw himself back into his hole in the limb 
and plug the opening behind him, before the limb breaks and falls. And 
this little creature accordingly appears to be so much of a philosopher as 
to understand the force of the winds and their action upon the limbs of 
the tree, so that lie can bring them into his service. He accordingly 
severs the limb so far that it will remain in its position until a strong gust 
of wind strikes it, whereupon it will break off and fall. 
But the most astonishing part of this feat remains to be noticed. The 
limb which he cuts off is sometimes only a foot in length and is, conse¬ 
quently quite light; sometimes ten feet long, loaded with leaves, and very 
heavy. A man by carefully inspecting the length of the limb, the size of 
its branches, and the amount of foliage growing upon them, could judge 
how fur it should be severed to insure its being afterwards broken by the 
winds. But this worm is imprisoned in a dark cell only an inch or two 
long, in the interior of the limb. How is it possible for this creature, 
therefore, to know the length and weight of the limb, and how far it 
should be cut asunder ? A man, moreover, on cutting a number of limbs 
of different lengths, so far that they will be broken by the winds, will find 
that he has often miscalculated, and that several of the limbs do not break 
off as lie designed they should. This little worm, however, never makes a 
mistake of this kind. If the limb be short, it severs all the woody fibres, 
leaving it hanging only by the outer bark. If it be longer, a few of the 
woody fibres on its upper side are left uncut in addition to the bark. If it 
be very long and heavy, not more than three-fourths of the wood will bo 
severed. The annexed figures represent the severed ends of limbs of different 
