Slit sensilla

The slit sensilla, also known as the slit sense organ, is a small mechanoreceptory organ or group of organs in the exoskeleton of arachnids which detects physical deformation or strain due to forces experienced by the animal. The organ appears in the vast majority of discovered arachnids, and is "remarkably consistent" in location and direction within each order. The arachnid slit sensilla corresponds to the campaniform sensilla found in insects.