Takagi, S., & Kawai, S. 1973 Discovery of Protancepaspis in Japan, with a review of the genus (Homoptera: Coccoidea).. Kontyû 41: 44-52.

Notes: P. torreyae n. sp.; taxonomic relation between Protancepaspis and Ancepaspis is discussed; boundary between Diaspididae and Phoenicoccidae is also discussed; definition of the genus Protancepaspis host and distribution; P. torreyae and P. bidentata compared.