T04 
STRANGE DWELLINGS. 
wood and the bark. She then deposits her eggs regularly along 
the cylindrical tunnels, and in most cases retreats to the entrance, 
and there dies, her body forming a natural stopper. In due time 
the eggs are hatched, producing a number of very minute white 
grubs, which immediately begin to feed, the substance of the 
tree being the only diet of this insect in every stage of existence. 
Urged by a wonderful instinct, each grub arranges its body at 
a right angle with the burrow in which it was hatched, and so 
eats its way steadily outwards. 
When the grubs have made some progress, the wisdom of this 
arrangement becomes evident. As they increase in size, the 
burrows necessarily increase with them, so that if they had all 
started parallel with each other, the tunnels would coalesce and 
the grubs be unable to procure their proper amount of food. As, 
however, the tunnels radiate like the spokes of a wheel, they 
very seldom interfere with each other, their radiation more than 
keeping pace with their increasing size. It will easily be seen 
by reference to the illustration, that if a number of these beetles 
attack a tree, the bark is gradually separated from the woody 
portion, and that, as in all exogenous trees the nourishment is 
derived from the bark, the tree must die as soon as the functions 
of the bark are suspended. 
The well-known 4 worm-eaten ’ appearance of furniture is 
caused by certain beetles belonging to another family. As may 
be seen from the dimensions of the tunnels, the insects are very 
small, and their bodies are nearly cylindrical. The ravages which 
these beetles cause are fatal to all who happen to possess old 
furniture, but Mr. Westwood mentions that one common species, 
Ptilinus pectinicornis, completely destroyed a new bedpost, in 
the short space of three years. There is but one known method 
of killing the insects which have already taken possession, and 
of preventing others from following their example, namely, 
by injecting a solution of corrosive sublimate into the holes, 
and then treating the whole of the surface with the same 
poisonous liquid. I need perhaps scarcely mention, that insects 
which are popularly called Death-watches, belong to this 
i 
