Sounds exactly like the borer beetles we have here in NZ. Plagiarized from a
website (http://www.pest.co.nz/borer.htm ):
The common borer attacks only seasoned timber, and damage is usually confined to
sapwood. It is not uncommon for borer damage to cause collapse of flooring or
floor joists. This borer has a four stage life cycle as follows:-
Adults: Small brownish beetle, 2.5-5.0mm long, recognisable by the head shaped
like a hood. Adult borer emerge between November and March and live for about
one month. Adult borer do not feed, they only reproduce.
Eggs: Females lay their eggs in wood cracks and crevices or in old exit holes.
Larvae: The eggs hatch in about three weeks. Each egg produces a larvae, which
is C-shaped, creamy white with a brown head, about 7mm long. The larvae bore at
random in the timber, coming nearer to the surface when ready to pupate.
Pupae: After some three to four years as a larvae, the insect is ready to
pupate. A small chamber is excavated just below the surface of the timber in
which to pupate. Pupation lasts four to eight weeks. While in this stage the
insect changes in form to an adult. The adult now emerges from the wood,
leaving a small round hole about 1.0-1.5mm in diameter. This is accompanied by
dust and is often the first indication of borer.
Your problem may be a relative of this beast.
I couldn't decide where to post this question, but thought one of you
woodworkers might know an answer to my problem. I recently bought some
rustic cedar furniture hand made in Mexico. Tonight I noticed a small pile
of sawdust at the bottom of one barstool leg (about 1 teaspoon). There are
holes in the leg and they vary in diameter from about the size of a
mechanical pencil lead to about 1/8 inch. Any idea what may be boring
around in there and how I might kill them? The cedar is natural with only a
Thanks in advance,