Above picture is of a frass ‘toothpick’ sticking out from trunk of tree.

Above pictures is of the oviposition chamber and larval gallery of one of the bark beetles, Xylosandrus spp.

Above picture is of the bark beetle, Xylosandrus germanus (ambroisa beetle)

Above picture is of the bark beetle, Xylosandrus crassiusculus (granulate ambrosia beetle)

The above pictures were provided by various authors (imbedded in photo) via bugwood.org