The classification follows Brues et al. (1954) with the following exceptions. The Acarina are arranged according to Dr. J. H. Camin (personal communication, 1955). Family Eupelmidae of the Hymenoptera follows the classification of Peck (1951). Class ARACHNIDA In this class, representatives of at least four orders have utilized cockroaches as food: the whip scorpions, scorpions, spiders, and mites. Apparently none of these feed exclusively on cockroaches, but the Philippine forest scorpion _Heterometrus_ (=_Palamnaeus_) _longemanus_ seems to prefer blattids to other insects (Schultze, 1927). Order PEDIPALPIDA Family THELYPHONIDAE =Mastigoproctus giganteus= (Lucas) _Synonymy._--_Thelyphonus giganteus_ Lucas [Dr. R. E. Crabill, personal communication, 1958]. _Experimental prey._--Cockroaches, U.S.A. (Marx, 1892, 1894): Immature whip scorpion captured and fed on one or two cockroaches a week. It lived on this diet for about two years. =Mastigoproctus= sp. _Common name._--Whip scorpion. _Experimental prey._--_Blattella germanica_, U.S.A., Florida [Dr. B. J. Kaston, personal communication, 1953]. Order SCORPIONIDA Pocock (1893) noticed that a scorpion whose pectines had come in contact with a cockroach immediately turned back and ate the insect. He concluded that the scorpion detected the cockroach by means of the pectines. However, Cloudsley-Thompson (1955) has demonstrated that the main function of the pectines is probably the detection of ground vibrations. He accounted for Pocock's observation by the presence of sensory spines (presumably tactile) which project from beneath the pectines. In a house in Arizona, Lyon (1951) observed over 60 scorpions living in a kitchen cabinet that enclosed a sink. They were apparently thriving on a heavy infestation of cockroaches. Stahnke (1953) stated that he used _Periplaneta americana_ as the principal food for scorpions at the Poisonous Animals Research Laboratory of Arizona State College. Cloudsley-Thompson (1955a) cited cockroaches as one of the arthropods that scorpions feed upon. Family BUTHIDAE =Buthus australis= (Linnaeus) _Synonymy._--_Androctonus australis_ [Crabill, personal communication, 1957]. _Experimental prey._--Cockroaches, England (Cloudsley-Thompson, 1955a): This African species ate at least one cockroach per week during the summer months. It can, however, survive four months' starvation and is particularly adapted to a dry climate (Cloudsley-Thompson, personal communication, 1956). =Centruroides gracilis= (Latreille) _Experimental prey._--_Periplaneta americana_, U.S.A. (Roth, unpublished data, 1953): Scorpion collected in Florida by Roth and identified by Dr. M. H. Muma. =Centruroides hentzi= (Banks)