INSECTS INJURIOUS TO THE OAK. 29 
the bark and scored the wood in directions radiating on one side of the 
place of oviposition; in one case a mine went directly across the one 
next to it. 
The following beetles are not known with cer- 
tainty, but supposed by Harris and also by Fitch, 
from their frequent occurrence on the oak, to in- 
jure that tree: 
19. THE Sitky TIMBER-BEETLE. 
Lymexylon sericeum (Harris). 
Order COLEOPTERA; family LYMEXYLONID. 
Boring small long cylindrical burrows in the 
wood of the oak, probably, and other trees; a 
slender odd-looking worm with six legs placed 
.on its breast, a prominent hump upon its neck, 
and a leaf-like fleshy appendage at the end of its 
back; changing into a long narrow chestnut- 
brown beetle, 0.50 long, bearded with short, shin- 
ing, yellowish hairs, giving it a silky luster; its 
eyes large and almost meeting together above 
and below, and its wing-covers tapering and 
shorter than the body. See Harris’ Treatise, 
p. 51. (Fitch.) 
20. THE AMERICAN TIMBER-BEETLE. 
Hylecetus americanus (Harris). 
Order COLEOPTERA; family LYMEXYLONID&. 
A worm very similar to the preceding, but with 
a straight sharp-pointed horn at the end of its 
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Fic. 6.—a, larva; a, pupa, and adult of the oak Fic. 7.—Track probably made by Magdalis 
bark weevil, M. olyra (from Packard). olyra (from Packard). 
back in place of a leaf-like appendage; changing into a pale brownish red beetle 
0.40 long; its wing-covers, except at their base and its breast, black, its eyes small, 
and a glassy dot on the middle of its forehead resembling a small eyelet. 
(See Harris’ Treatise, p. 51.) 
This and the preceding are very rare insects, and their larve have never been de- 
tected, but are inferred by Dr. Harris to inhabit oaks and to have the singular forms 
above indicated, from the analogy of the perfect insects to two European species, 
Foreign writers, Lsee, are misled by Dr. Harris’s account, into supposing that it is 
authentically ascertained that our insects coincide in their larva state with the Euro- 
pean species. (Fitch). 
