368 THE ENTOMOLOGIST. 
his account of its economy is the first we have. Ratzebourg 
has, however, given us a much more complete life-history in 
his ‘ Forst-Insecten Kafer,’ in which work he has figured the 
insect in all its stages. Ithas sometimes been most abundant 
in the dockyards of France, perforating the oak-timber and 
reducing it to powder. It has been found that in all stages 
this pest can be destroyed by immersing the timber in water. 
In the oak forests of Northern Europe it abounds; but in 
England it is go great a rarity, that a single specimen, taken 
in Windsor Forest, was esteemed a great treasure. The 
second insect is a marine wood-louse of very small size, but 
of great destructive powers: its food consists exclusively of 
timber, for, on examining the contents of its stomach, these 
have been found to consist entirely of comminuted wood. 
Unlike Lymexylon, which is killed by immersion in water, 
Limnoria only feeds on timber that is either partially or 
entirely submerged. Mr. Coldstream has collected a vast 
number of facts respecting this creature, and has published 
them in the ‘Edinburgh New Philosophical Journal’ for 
1834. From this it appears that it commences its ravages on 
a piece of wood by excavating the soft parts, leaving those 
harder parts which mark the boundaries of annual growth, - 
and subsequently attacks these, the portion consumed being 
under water, or, at any rate, below high-water mark. During 
the building of the Bell-Rock lighthouse it was necessary to 
erect a temporary wooden building, in which the engineer 
and his assistants resided, and which was supported by 
twelve large beams of Memel fir, fixed in bolt-holes cut 
in the rock; the sides of these beams were charred and 
pitched, but the bottoms, which closely fitted to the holes, 
were left naked. In the second year the edges of these 
timbers were in a state of decay, owing to the borings of the 
Limnoria. The logs of Norwegian pine, laid down to support 
the temporary tramroads, were greatly injured; the timbers 
at first ten inches square, in four years were reduced to 
seven inches, thus losing at the rate of nearly an inch a year. 
In some instances the house timbers were so completely eaten 
away at the bottom that they stood clear of the rock, 
supported only by the bolts and stanchions. The piles 
supporting the timber-bridge at Montrose were so destroyed 
by the boring of the Limnoria that the whole structure was 
