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: A depression caused by erosion by water or ice. Low-lying land bordered by higher ground; especially elongate, relatively large gently sloping depressions of the Earth's surface, commonly situated between two mountains or between ranges of hills or mountains, and often containing a stream with an outlet.
