The triozid genus Petalolyma Scott, 1882 is reviewed, and the monotypic genus Torulus Li, 1991, syn. nov., is considered a junior subjective synonym. Torulus sinicus is transferred to Petalolyma as P. sinica (Li, 1991), comb. nov., producing a secondary homonym of P. sinica Yang & Li, 1984, for which the replacement name Petalolyma lii Liao & Burckhardt, nomen nov. is proposed here. Adults and fifth instar immatures of Petalolyma vittata Liao & Burckhardt, sp. nov. are described and illustrated. The new species induces marginal fold galls on leaves of Ilex ficoidea (Aquifoliaceae). The previously unknown male and female of P. lii and P. nigra, respectively, are described and illustrated, and Petalolyma castanopsis Li & Yang, 1991 and P. fujianensis Li & Yang, 1999, syn. nov., are synonymised. Petalolyma hyalina (Kuwayama, 1910) is considered a nomen dubium as the original description is not diagnostic and the type material cannot be found. Hence, Petalolyma currently includes 13 valid species whose host plant and biogeographic patterns are briefly discussed. Identification keys for the adults and fifth instar immatures are provided for the Taiwanese species.
Sternorrhyncha, Psylloidea, New species, New synonymies, Taxonomy, Marginal fold gall
