Wood-boring wasp ("horntail")
Siricidae
Adult female wasps are large and thick-waisted, with a hornlike ovipositor at the end of the abdomen. They sometimes emerge from recently milled dimension lumber in newly constructed homes. Emerging wasps damage walls (sheetrock, plaster, wallpaper, etc.) but do not re-infest.
Larvae mine in Douglas-fir, true firs, pine, and other conifers. Fire-killed trees are most frequently attacked, though windblown or insect-damaged trees are also susceptible.
Plug emergence holes and repair the surface. Since horntails will not re-infest other parts of the structure, chemical control is unnecessary.