46S 
ANNUAL REPORT OF NEW-YORK 
CHESTNUT. TRUNK. 
15. THE CHESTNUT .—Castanea vesca. 
AFFECTING THE TRUNK AND LIMBS. 
We have never noticed any boring insect of a large size in the 
wood of this tree. But the durability of its timber, which is so 
highly valued, particularly for fence rails and posts, is much im¬ 
paired by small insects which perforate it with holes that are only 
of sufficient size to admit the head of a pin, but which are often 
excessively numerous, and being pierced directly inward towards 
the heart of the tree become filled with wet from every shower. 
The decay of the wood is hereby greatly accelerated. These per¬ 
forations are made by a slender cylindrical six-footed worm, half 
an inch long, of a white color and brownish yellow at each end, 
its apex cut off abruptly and obliquely and edged with small 
black teeth. The beetle that is produced from this worm is not 
yet ascertained. 
Rails which have been pierced with pin-holes by this insect 
should always be placed in the fence with their sap side down¬ 
wards, as it is upon this side that these holes mostly open. 
195 . Two-toothed Silvanus, Silvanus bidentatus, Fab. (Coleoptera. Mycc- 
tophagidae.) 
Under the bark of logs and decaying trees, probably loosening 
the bark from the wood, a minute, narrow, flattened beetle, of a 
light chestnut-brown or rust-color, its thorax longer than wide, 
slightly narrowed towards its base and with a small tooth pro¬ 
jecting outwards at each of its anterior angles. Length 0.10 to 
0 . 12 . 
This is a European insect, which, like a kindred species, the 
Surinam Silvanus, has now become perfectly naturalized and as 
common throughout the United States as it is in its native haunts. 
On stripping the bark from recently cut logs of chestnut and of 
oak, this minute beetle, which is so flattened and thin that it can 
creep into the slightest crevices, will be found frequently in con¬ 
siderable numbers. We have several other insects which inhabit 
similar situations and are so much like this that a careful exami¬ 
nation is requisite to determine their respective species. By the 
