Four new species of oak gallwasps of the genus Dryocosmus: D. pentagonalis, D. triangularis, D. carlesiae, and D. testisimilis are described from Taiwan. They induce galls on one species of Castanopsis and one species of Lithocarpus (Fagaceae). Data on the diagnosis, distribution, and biology of the four new species is given. A key for Dryocosmus species identification of Taiwan is provided. Final comments discuss the polyphyletic nature of the Dryocosmus genus, emphasizing the urgent need for its revision.

Acoustic communications are prevalent in insects, and evidences show that acoustic characteristics could be used in taxonomy. With regard to Psylloidea, acoustic signals of 37 species have been recorded and described, indicating that acoustic knowledge of psylloids is limited compared with 3,800 described psylloid species, although the comparison emphasized on males only. Because many new psylloids were named based only on variations in the structure of male genitalia and host-plant records, we asked whether acoustic signal could be supplementary characteristics in recognizing the species. We studied the acoustic behavior of three closely related species of Cacopsylla Ossiannilsson, each explore and use distinct species of Pittosporum Banks, to examine the necessity of intergender duets and to determine their potential relevance in taxonomy. We conclude that duets are necessary for mating. The initial call and active search are usually made by the male. Females usually stay stationary and respond passively. Signals from males include two sections: a series of chirps followed by a long trill, whereas those from females include a long series of repeated chirps. The results of a discriminant analysis of acoustics showed that the three species of Cacopsylla were distinguishable from acoustic characteristics. We conclude that acoustic signals of psylloids provide useful information for the taxonomy of psylloids, especially at the species level.

Recent years have seen rapid advances in the study of Fagaceae-associated gall wasps (Hymenoptera: Cynipidae) of the Eastern Palaearctic and the Oriental (EPO) regions, for both the gall inducing Cynipini (commonly termed oak gall wasps though many species gall non-oak Fagaceae) and the predominantly inquiline tribes Synergini and Ceroptresini. This process has propagated some taxonomic errors and involves many taxa whose taxonomic status is uncertain. To provide a stable foundation for further advance, here we review the taxonomic status of the 212 species (133 oak gall wasps and 79 oak cynipid inquilines) that have been described or recorded in these regions. Of this total, we treat 171 as valid species names (103 oak gall wasps and 68 oak cynipid inquilines) in 20 genera; 22 as synonym names, 13 as incertae sedis, three as nomen dubium, and three as species inquirenda. Callirhytis kunugicola Shinji, 1944 is proposed as syn. nov. of C. kunugicola Shinji, 1943, as Shinji described the same species twice. For all valid species names, we provide taxonomic references, synonyms, and geographical distributions. We summarize what is known of host plant associations and gall locations for gall inducers, and host associations for inquilines. We discuss geographic patterns in the known richness of currently valid species for both groups of organisms, and place this in the context of the biogeography of available Fagaceae host plants. We provide a brief historical review of the study of oak gall wasps and their inquilines in the EPO regions.

Eight new species of cynipid gallwasps, Cycloneuroterus abei Melika & Tang, C. ergei Tang & Melika, C. gilvus Melika & Tang, C. globosus Melika & Tang, C. jianwui Tang & Melika, C. lohsei Melika & Tang, C. tumiclavus Tang & Melika, C. uraianus Tang & Melika, from Taiwan and mainland China are described. Descriptions, diagnoses, biology, and host associations for the new species and a key to all Cycloneuroterus species are given. All taxa are supported by morphological and molecular data. Seven newly described species induce galls on Quercus subgenus Cyclobalanopsis, while one, C. uraianus, induces galls on Castanopsis. This is the first Cycloneuroterus species known to associate with Castanopsis.