719 
No. 145.] 
burrow, as it bores a round hole, upward, in the solid wood. 
This hole runs slightly inwards, towards the centre of the tree, 
and then outwards, so that when it is completed its upper end is 
perforated through the sap-wood, and is only covered by the bark. 
The lower flat portion of its burrow is by this 
time stuffed in every part with its castings, 
whilst the long cylindrical passage above is 
still empty. As if fearful that these castings, 
being so fine and dry, might sift out, and thus 
leave an open passage for some marauding in¬ 
sect or other enemy to crawl in and destroy it 
during its defenceless pupa state, and that it 
may, during this period of its life, be securely 
held in the middle of its cylindrical hole, the 
worm now turns itself around, (as I think, for 
it is impossible to conjecture how otherwise 
this long round cavity becomes filled in the 
manner in which we usually find it,) and with 
its jaws strips a quantity of woody fibres from 
the inner walls of the middle part of its bur¬ 
row, thus enlarging this part sufficiently to give 
it ample room to repose here in its pupa state, 
w’hen its body becomes more short and broad 
than it has previously been. With these fibres 
of wood, which are from a half to three fourths of an inch in 
length, it firmly plugs up all the lower part of its burrow above 
the flat excavation in the sap-wood, placing the fibres frequently 
in as regular order as the hairs of a mustache. And the castings 
w'hich it voids W’hen in this inverted position are crowded, and 
firmly packed together in the upper end of its burrow’. Thus 
the long cylindrical hole which it has bored becomes filled up, 
and securely plugged with woody debris at each extremity, leav¬ 
ing only a vacant space in its middle, where it is deepest sunk in 
the wood of the tree, for the insect to lie during its pupa state. 
The annexed cut will give an idea of these burrows and their 
contents, as they appear when the bark is removed and the wood 
cut away sufficiently to expose their whole length to view. 
Having now finished its labors and attained its growth it again 
