Dayus Mahmood, 1967

Webb, Michael D. & Xu, Ye, 2022, Review of the “ red ” Empoascini leafhoppers in the genera Baguoidea Mahmood, 1967, Dayus Mahmood, 1967 and Homa Distant, 1908 (Hemiptera, Cicadellidae, Typhlocybinae) from Asia and the West Pacific, Zoosystema 44 (22), pp. 549-563 : 552

Genus Dayus Mahmood, 1967

Dayus Mahmood, 1967: 39 . — Qin & Zhang 2007: 43 . — Yu & Yang 2013: 2 . — Qin et al. 2014: 1498 (key); 2021a: 229.

TYPE SPECIES. — D. elongatus Mahmood, 1967 , by original designation.

DISTRIBUTION. — Widespread in Asia and the Pacific.

REMARKS

This genus is tentatively regarded as distinct from Baguoidea (see Remarks under that genus). It differs only in having the basal group setae of the subgenital plate not blunt-tipped and in having an unusual ventral apodeme of the 8th abdominal sternite with a pair of short anterior lobes ( Fig. 4F ), and also found here with a series of short setae at the posterior lateral corner of the 8 th sternite. There is considerable variation among species in proportion of the vertex, size and colour, for example, in Dayus formosus the vertex is distinctly longer medially than next to eye but more or less the same in D. trifurcatus Yu & Yang, 2013 while the latter is yellow and not red as in some other congeners and very much bigger (two paratypes of D. trifurcatus [♂ and ♀] examined, NHM). A key to the Chinese species of the genus was given by Yu & Yang (2013). CHECKLIST AND DISTRIBUTION OF DAYUS SPECIES

D . bifurcatus Yu & Yang, 2013: 3, figs 1-9. China (Zhejiang).

D. elongatus Mahmood, 1967: 39 , plate 8, fig. 1. Malaysia ( Singapore).

D. euryphaessus ( Kirkaldy, 1907) : 68. Fiji, Australia (?).

D. formosus Dworakowska & Viraktamath, 1978: 544 , figs 33- 41. India, China (Hainan, Hong Kong new record, Taiwan).

D. furcatus Xu, Dietrich & Qin, 2021a: 231 , figs 10-17. Thailand.

D. lamellatus Qin & Zhang, 2007: 48 , figs 22-31. China (Fujian, Zhejiang).

D. lii Qin & Zhang, 2007: 45 , figs 1-12. China (Fujian).

D. membranaceus Qin & Zhang, 2007: 45 , figs 13-21. China (Fujian, Jiangxi).

D. serratus Yu & Yang, 2013: 4 , figs 24-30. China (Hainan).

D. takagii Dworakowska, 1971: 501 , figs 1-11. China (Sichuan, Hong Kong, Taiwan), Japan.

D. trifurcatus Yu & Yang, 2013: 3 , figs 10-23. China (Chongqing).

D. upoluanus ( Osborn, 1934) : 190, fig. 15. Western Samoa.

Figures

FIG. 4. — Dayus lamellatus Qin & Zhang, 2007: A, head and thorax, dorsal view; B, face; C, male pygofer, lateral view; D, aedeagus and connective, lateral view; E, aedeagus and connective,ventral view;F, male abdominal apodemes of third tergite (upper) and 8th sternite (lower);G, style; H, male pygofer internal process; I, subgenital plate, ventral view; J, male anal tube process, lateral view. Reproduced from Qin & Zhang (2007, figs 22-29), with permission from copyright holder.