Dayus motuoensis Ding, Yu & Yang sp. nov.

(Figs 37–51)

Description: Length. Male 3.5 mm.

Whole body red (Figs 37–40). Eyes grayish-black (Figs 37–40). Coronal suture reddish brown (Figs 37, 40). Legs red to light orange-red (Figs 38, 39, 40). Forewing with veins red to reddish-brown (Figs 37, 38, 41).

Head including eyes slightly wider than pronotum in dorsal view, coronal suture not reaching midlength of crown (Figs 37, 40). Face narrow and slender, convex in lateral view (Figs 38, 39). Head anterior margin roundly produced (Figs 37, 40). Forewing narrow, with veins RP, MP’ and MP’’+CuA arising from m cell, hindwing with CuA unbranched (Figs 41, 42).

Male ventral abdominal apodemes reaching the end of segment 4 and diverging (Fig. 43). Male pygofer with 13 rigid macrosetae, ventral dorsal bridge clearly defined, and ventral appendage with slightly sinuate and expanded, tapering to apex (Figs 44, 45, 46). Subgenital plate extends beyond pygofer side, with 4 A- group setae, 12 B-group spiny setae, 15 C- group setae, and 2–3 rows D-group setae (Figs 44, 45, 47). Paramere slim and curved, with tiny teeth and 5–6 fine setae subapically (Fig. 48). Connective fully united with the base of aedeagus (Figs 49, 50). Aedeagus shaft with apical process and midlength with bifurcate processes extended to different directions on each side (Figs 49, 50). Anal tube processes broad, curved, and tapering apically (Fig. 51).

.

Material examined. Holotype ♂, Dexing, Motuo, Xizang, China, 95.3078° E, 29.3262° N, 827.4 m, 29 June 2022, coll. Yan Ding. Paratypes: 1♂, Damuluo, Motuo, Xizang, China, 95.4641° E, 29.4937° N, 1569.48 m, 3 July 2023, coll. Yan Ding ; 1♂ Jingdong, Puer, Yunnan, China, 22 July 2022 , coll. Hong-Li He.

Etymology. The name of the new species is derived from the collecting location of type species (Motuo, Xizang, China).

Remarks. This species is similar to Dayus lii Qin & Zhang, 2007 mainly in body colour and the shape of the aedeagus. Both species have a pair of bifurcated lateral aedeagus processes (Figs 49, 50), but the new species differs from the latter in having the ventral pygofer appendage unbranched apically (Fig. 46), and the aedeagus processes located at the midlength of the shaft and oriented laterad (Figs 49, 50). In contrast, Dayus lii has the aedeagus processes arising subapically.

Distribution. China (Xizang, Yunnan).