Drilling flour is small sawdust that is produced by various insects that live inside the wood of various trees and make moves in it with the help of their upper jaws ( bark beetles , larvae of barbel beetles , cattails , etc.).
Drilling flour is in the passages that have been done by insects, and can also protrude out of the so-called. flight holes. Part of this flour lies in piles in front of the outlet openings, part crumbles. If the stroke of the insect takes place in the bark, then the drilling flour usually has a brownish color, and if the stroke takes place directly in the wood, it is whitish or yellowish.
Literature
- Encyclopedic Dictionary of F. A. Brockhaus and I. A. Efron . - S.-Pb .: Brockhaus-Efron. 1890-1907.