138 DESTRUCTION OF INSECTS. 
the wood, leaving only thin partitions between the gaileries it 
excavates in it; but as it never gnaws through the surface to 
the air, a stick of timber may be almost wholly consumed with- 
out showing any external sign of the damage it has sustained. 
The termite is found also in other parts of France, and particu- 
larly at Rochelle, where, thus far, its ravages are confined to a 
single quarter of the city. A borer, of similar habits, is not 
uncommon in Italy, and you may see in that country handsome 
chairs aud other furniture which have been reduced by this 
insect to a framework of powder of post, covered, and appa- 
rently held together, by nothing but the varnish. 
Destruction of Insects. 
It is well known to naturalists, but less familiarly to common 
observers, that the aquatic larvee of some insects which in other 
stages of their existence inhabit the land, constitute, at certain 
seasons, a large part of the food of fresh-water fish, while other 
larvee, in their turn, prey upon the spawn and even the young 
of their persecutors.* The larvae of the mosquito and the gnat 
are the favorite food of the trout in the wooded regions where 
those insects abound.t Larlier in the year the trout feeds on 
* T have seen the larva of the dragon-fly in an aquarium bite off the head 
of a young fish as long as itself. 
+ Insects and fish—which prey upon and feed each other—are the only forms 
of animal life that are numerous in the native woods, and their range is, of 
course, limited by the extent of the waters. The great abundance of the 
trout, and of other more or less allied genera in the lakes of Lapland, seems to 
be due to the supply of food provided for them by the swarms of insects which 
in the larva state inhabit the waters, or, in other stages of their life, are ac- 
cidentally swept intothem. All travellers in the north of Europe speak of the 
gnat and the mosquito as very serious drawbacks upon the enjoyments of the 
summer tourist, who visits the head of the Gulf of Bothnia to see the mid- 
night sun, and the brothers Lzestadius regard them as one of the great plagues 
of sub-arctic life. ‘‘ The persecutions of these insects,” says Lars Levi Les- 
tadius [Culex pipiens, Culex reptans, and Culex pulicaris], ‘leave not a mo- 
ment’s peace, by day or night, to any living creature. Not only man, but 
cattle, and even birds and wild beasts, suffer intolerably from their bite.” He 
adds in a note, ‘‘I will not affirm that they have ever devoured a living man, 
