| abstract | This paper describes two new species of the genus Tetranychus from China. Type specimens are deposited in the Institute of Zoology, Academia Sinica.
Tetranychus dunhuangensis, sp. nov. (figs. 1-12)
Female Length 471µ, including rostrum 529µ, width 278µ. Yellowish-green in colour. Palpus with terminal sensellum two times as long as wide; dorsal sensellum rod-like, shorter than the terminal one. Integument with longitudinal striae between the third pair of dorsocentrals and also between the inner sacrals, forming a diamond-shaped pattern between these setae. Empodium I-IV with mediodorsal spur, that of empodium I more obvious.
Male Length 279µ, including rostrum 366µ, width 147µ. Terminal sensellum two and a half times as long as wide; dorsal sensellum shorter than terminal one. Shaft of aedeagus wider and bent dorsad. Terminal knob minute, forming an angle with the axis of shaft, the anterior projection short and blunt, the posterior projection rather long and blunt distally.
Holotype ♂, allotype ♀, paratypes 26♀♀ 8♂♂, 19. VII. 1976, all taken on cotton. Dunhuang, Gansu Province. A series of paratypes including 1♂ on pear, 3♀♀ on sun-flower, 9♀♀ on Calystegia hederacea, 13♀♀ 2♂♂ on sorghum, 12♀♀ 2♂♂ on bean, on 17-20, VII. 1976, from same locality.
Tetranychus dunhuangensis is distinct from all other known members of this genusin the shape of the aedeagus.
Tetranychus agropyronus, sp. nov. (figs. 13-21) Female Length 437µ, including rostrum 497µ, width 248µ. Yellowish-green incolour. Palpus with terminal sensellum twice as long as wide, dorsal sensellum equal to the terminal one in length. Integumentary striae transverse or irregular between third pair of dorsocentrals, but irreqular between inner sacrals and transverse in the area between these setae.
Male Length 284µ, including rostram 359µ, width 155µ. Palpus with terminal sensellum two and a half times as long as wide, dorsal sensellum about equal to the terminal one in length. Aedeagus bent dorsad, the terminal knob forming an angle with the axis of shaft, the anterior projection blunt, the posterior projection acute, and with an angle distal to 1/3-1/4 of the dorsal margin of the knob.
Holotype ♀ and paratypes 14♀♀ 1♂, 30. VII. 1976, Yinchuan, Ningxia, on Agropyron cristatum. Allotype ♂ and a series of paratypes 20♀♀ 5♂♂, on Agropyron cristatum; 4♀♀ 1♂ 1 nymph on wheat, 8♀♀ 3♂♂ 1 nymph on mulberry, taken on 17-20. VII. 1976, Dunhuang, Gansu Province.
Tetranychus agropyronus is similar to Tetranychus sinhai Baker in colour of body, shape of aedeagus and pattern of hysterosomal striae, but differs from the latter in the neck of aedeagus being longer and with an angle distal to 1/3-1/4 of the dorsal margin of terminal knob and in the setation of legs in both sexes. |