Three new species of the leafhopper genus Dayus Mahmood from China (Hemiptera, Cicadellidae, Typhlocybinae, Empoascini)

Abstract Three new species of the Oriental empoascine leafhopper genus Dayus Mahmood are described from China: D. bifurcatus sp. n., D. trifurcatus sp. n. and D. serratus sp. n. A key to distinguish all Chinese species of the genus is provided.


Introduction
The Oriental typhlocybine leafhopper genus Dayus was established by Mahmood in 1967 with D. elongatus Mahmood (Singapore) as its type species. Subsequently, Dworakowska (1971) described D. takagii Dworakowska (Japan) and transferred D. upoluanus (Osborn, 1934) (Western Samoa) and D. euryphaessus (Kirkaldy, 1907) (Fiji) to the geuns, Dworakowska and Viraktamath (1978) added a new species: D. formosus from China (Taiwan) and Qin and Zhang (2007) added three new species from China: D. lii Qin & Zhang, D. membranaceus Qin & Zhang and D. lamellatus Qin & Zhang. Here we describe three new species of Dayus from China and provide a key for the separation of all known Chinese species. The specimens examined are deposited in the Institute of Entomology, Guizhou University, Guiyang, Guizhou, China (GUGC) and The Natural History Museum, London (BMNH).

Materials and methods
The methods and terminology follow Zhang (1990) except for the nomenclature of wing, for which we follow Dworakowska (1993). Male specimens were dissected under a MOTIC B1 SMS-168 SERIES microscope. Figures were made using an OLYMPUS CX41 and enhanced using Adobe Illustrator CS4. Pictures were taken with VHX-1000C and dealt with by Adobe Illustrator CS4. The body length is measured from the apex of the head to the apex of the forewing.  (Figs 5,17,27) with basal group of macrosetae and one or two oblique rows of more distal macrosetae. Connective (Figs 7,19,29) completely fused with the base of aedeagus. Aedeagus (Figs 8,20,30) with basal apodeme absent; shaft strongly curved posteriorly at base with one or two pairs of processes. Description. Length, male 3.0 mm. General color reddish to reddish brown. Both sides of coronal suture with a brownish patch.

Key to the Chinese species (males)
Male ventral abdominal apodemes reaching segment 5 (Fig. 4). Male pygofer with dorsoposterior margin sinuate; pygofer appendage with dorsal margin sinuate in lateral view, tapering to apex (Fig. 3). Subgenital plate about twice as broad basally than distally, with three lateral macrosetae in basal group, an oblique line of 14 macrosetae and several long fine setae subbasally to apex and ca.12 short microsetae at outer margin (Fig. 5). Paramere as in Fig. 6. Aedeagus shaft long and narrow, slightly depressed dorsoventrally, similar in width throughout length in ventral view, with a pair of short bifurcate apical processes (Figs 7, 8). Anal tube process short (Fig. 9).
Etymology. The new species name alludes to the pair of apical bifurcate aedeagal processes.
Remarks. The new species can be distinguished mainly by the shape of the aedeagal shaft and its process configuration as noted in the description.
General color yellowish.
Etymology. The new species name alludes to the trifurcate processes of the aedeagus.

Remarks.
The new species can be distinguished mainly by the strongly sinuate posterior margin of the pygofer and shape of the aedeagal shaft and configuration of its process as noted in the description.
General color yellowish. Male ventral abdominal apodemes reaching segment 3 (Fig. 25). Male pygofer ( Fig.  24) with dorsoposterior margin concave, tapering caudally; ventral appendage with dorsal margin slightly sinuate, tapered to acute apex. Subgenital plate slightly broader basally, with 9 apically rounded lateral macrosetae in basal group, an oblique line of 12 macrosetae and several long fine setae sub-basally to apex and ca.32 short microsetae at outer margin (Fig. 27). Parameres as in Fig. 28. Aedeagus shaft long, basal half strongly dorsoventrally depressed, distal half narrow and cylindrical, serrate laterally at base on dorsal surface; with two long processes arising at midlength on each side of shaft, basally each process with a lateral lamellate serrate lobe (Figs 29,30). Anal tube process short (Fig. 24).
Etymology. The new species name is derived from the serrations at midlength of the aedeagal shaft and base of the aedeagal processes. Remarks. The new species can be distinguished mainly by the relatively rather uniform width of the subgenital plate and shape of the aedeagal shaft and configuration of its process as noted in the description.