Definition: Insect mouthparts that are concealed inside the head by folds of the head capsule. The mandibles and maxillae are located inside the oral chamber, and only the tips of the mouthparts protrude from the oral opening.
Definition: Organic matter in soil which has reached a point of stability, where it will break down no further and might, if conditions do not change, remain essentially as it is for centuries, or millennia.
