Vespoids are the little bugs that are annoying to kill. Most of the time they will explode when they die, leaving no pieces to carve. To get easy Vespoid and Hornetaur (beetle) pieces, get a Hunter's Knife and upgrade it to a Hydra Bite so
that it adds poison. With that weapon, when you hit the Vespoids you will poison them and they will most likely drop to the ground, leaving behind a carcass to carve from.