PROC. ENTOMOL. SOC. WASH. 85(4), 1983, pp. 753-761 THE WHITE PEACH SCALE, PSEUDAULACASPIS PENT AGON A (TARGIONI-TOZZETTI) (HOMOPTERA: DIASPIDIDAE): EVIDENCE THAT CURRENT CONCEPTS INCLUDE TWO SPECIES' John A. Davidson, Douglass R. Miller, and Sueo Naflahara (JAD) Department of Entomology, University of Maryland, College Park, Maryland 20742; (DRM, SN) Systematic Entomology Laboratory, IIBIII, Agri-cultural Research Service, USDA, Beltsville, Maryland 20705; (SN) formerly with Plant Protection and Quarantine, Animal and Plant Health Inspection Service, USDA. Abstract. — EyidQnce, is presented that the current species concept of the white peach scale, Pseudaulacaspis pentagona (Targioni-Tozzetti) is incorrect and ac-tually includes two species, P. pentagona and the white prunicola scale, P. prun-icola (Maskell). Characteristics used to distinguish between the species include body microstructures, egg colors, host differences, distribution patterns, life history differences, and host transfer data. New data are given on synonymies, mor-phologies, hosts, distributions, and life histories. First instars and second-instar males of each species were studied but no conspicuous species differences were found. The white peach scale, Pseudaulacaspis pentagona, was described by Targioni-Tozzetti in 1886 from several localities in Italy. Since then, other alleged species have been described and subsequently synonymized with P. pentagona, including Pseudaulacaspis prunicola (Maskell, 1895). In the course of research on the economic scale insects of the United States, we noted that Kawai (1980) had treated P. prunicola as a species distinct from P. pentagona. Since P. prunicola has not been reported from the United States, we investigated the distinctiveness of these species further. The purpose of this paper is to demonstrate that the traditional concept of P. pentagona is partially incorrect, and that this taxon actually is composed of two cryptic species. The second species is P. prunicola. Materials and Methods The preliminary search for taxonomic characters involved a detailed exami-nation of 1 5 specimens of each species from as many localities and hosts as possible. After preliminary morphological differences were discerned, 70 speci-mens of P. prunicola and 74 specimens of P. pentagona were used for determi-' Scientific Article No. A-3188, Contribution No. 6257 of the Maryland Agricultural Experiment Station, Department of Entomology.