In dry climates the water may evaporate before reaching the water table, leaving behind a hard pan layer of calcium carbonate. The resulting layers, called horizons, have different characteristics, different colors, different textures. Horizons, particularly the O or organic horizon, have a host of tiny and not so tiny arthropod inhabitants. Some have incredible adaption to their soil homes. One such beast is the ant lion, the larval stage of the lace wing.
Adults bear a general resemblance to dragonflies with short knobbed antennae.
Ant lions make pits in sandy soil about the diameter of a silver dollar. Perhaps you have seen them in your yard. Mine are underneath the strawberry tree on the south side of the house. Ant lions lie with fearsome pinchers just showing in the sandy bottom of the pit, waiting patiently for an ant to stumble in. Ant lions are sensitive to vibrations and make quick work of foolish ants.