The venom of Pyemotes zwoelferi Krczal, produced in glands in the pedipalps and injected by the mite while biting, can paralyze third-instar larvae of the greater wax moth, Galleria mellonella (L.), in about 30 min. Oxygen consumption of paralyzed larvae dropped 55% below that of unparalyzed individuals, to a level similar to that found in larvae artificially immobilized by ligating them between the head and the thorax. Oxygen consumption of ligated larvae increased, ho ever, after they were bitten by the mites. The mite toxin thus appeared to have no direct effect upon respiratory metabolism, the decrease in oxygen consumption being a secondary feature associated with the suppression of motor activity by neuromuscular paralysis. Paralyzed larvae are not “dead” physiologically, as they maintain a relatively high metabolic rate in their various organs. Female bites already are supplied with venom when they emerge from the parent, and can immediately attack and paralyze suitable prey. Their behavior in doing so, and in subsequent feeding upon the host, is described.