The Japanese and Taiwanese cockroach species belonging to the tribe Ischnopterites appear taxonomically in a chaotic condition. From this area Karny and Shiraki described in total 12 species and one variety of "Ischnoptera", but eight of them were rearranged in Princis' Catalogue into four genera, and four were left as "species incertae sedis." While accumulating material since 1950 from Japan and Taiwan I checked the type-specimens preserved in Hokkaido University, National Taiwan University, and Karny's material (Hans Sauter Collection) now preserved in the Deutsches Entomologisches Institut, Eberswalde, East Germany. In the present work I started from a recognition of a well-known American species, Symploce capitata (Saussure) which seems rather near to the type-species, Symploce hebardi Princis. In this paper an attempt was made to revise nine species and two subspecies which seem referable to the genus Symploce sensu strictu. A subsequent part of this revision will treat the representatives of a redefined genus Episymploce. Since a comprehensive world revision of Ischnopterites has not been made, the recent splitting of Symploce and its allied forms seems to embody various problems which should be revised in a future occasion. Symploce capitata (Saussure)(Fig. 1,A-C; Fig. 4,A, B; Fig. 5,A-J) As an only American Symploce species at hand I gave here a description and illustrations including the male phallosome. Although I don't believe that this species, with its brachypterous female, is a very good example of American Symploce the shape of the phallosome gives much different impression from Eastasiatic representatives. 1a. Symploce striata striata (Shiraki) (Fig. 1,D-F; Fig. 4,C; Fig. 6,A-D) A medium-sized chestnut colored species with yellowish costa of the wings. Female wings are more or less shortened. For structural details see accompanying figures. Found among decayed vegetable matters and hibernates in a mature larval stage, adults are frequent in early season. This South Japanese species ranges from southern coast of Honshu (northernmost locality is Ako, Hyogo Pref.) to Takarajima in the Central Ryukyus, including, probably, whole Shikoku, Kyushu, Tsushima and Tanegashima, but absent from Amamioshima, Okinawa and Yayeyama Islands. 1b. Symploce striata wulaii subsp. nov. (Fig. 1,G, H; Fig. 4,D; Fig. 6,E-G) Allied closely to the preceding nominate subspecies but slightly larger in size. Body coloration almost same with it, but is provided with paler face in the males. The tergite of the terminal abdominal segment has median tuft of hairs in the male. Confined to Taiwan. 2. Symploce yayeyamana sp. nov. (Fig. 1,I; Fig. 7,A-D) This may be the vicariant geographical race of the former two. The most remarkable character is the long and sharply pointed styli on the hypandrium. Only one male specimen taken from Ishigaki Island was available. 3a. Symploce gigas gigas sp. nov. (Fig. 2,A-D; Fig. 4,E; Fig. 8,A-F) A large pale brownish species, misidentified by Karny (1915) and Shiraki (1931) to be "Ischnoptera australis Saussure 1863" from Australia. For diagnostic characters refer accompanying figures. Abdominal tergites have the tuft of hairs on 1,7 and 10 segments. Found from Yayeyama Islands (Iriomote and Ishigaki) and Taiwan, The Taiwanese materials are always slightly smaller in size but no racial difference is recognized. 3b. Symploce gigas okinawana subsp. nov. (Fig. 2,E, F; Fig. 4,F; Fig. 9,A-H) Differing from the nominate form by the smaller and slender body, the shape of prothoracic tergite is distinctly narrow. Mainly taken from Okinawa Island. Those taken from Amami and Okinoerabu Islands were females, and one female from Iriomote Island is a very small, short-winged insect. 4. Symploce japonica (Shelford) (Fig. 3,A, B; Fig. 4,G, H; Fig. 10,A-F) For this species refer my 1974 paper. Distributed in South Kyushu, and sou

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