Holotype. China • ♂; Tibet, Gyirong County; 28.404N, 85.332E; 3300 m; 20-VII-2017; Chao Wu leg.; IZCAS. Paratypes. China • 4 ♂ 6 ♀; Tibet, Gyirong County; 28.397N, 85.351E; 2800~3300 m; 18~21-VII-2017; Chao Wu leg.; IZCAS • 3 ♂ 3 ♀; ditto; CWC • 1♀; ditto; CJZ • 1 ♀; Tibet, Gyirong County; 28.363N, 85.339E; 2672 m; 1-VIII-2018; Jin-Cheng Liu leg.; CWC.

Holotype. Male. Slim (Figs 1B, C, 2, 3A, 3C).

Head: lanceolate. Paired juxtaocular bulges united into a conical extension with a complete median dorsal suture and a deep vertical ventral groove (Fig. 4B). Compound eyes long, oval, not bulging. Three ocelli, small, not obvious (Fig. 4B). Lower frons approximately trapezoidal, approximately as wide as high.

Thorax: pronotum longer than head, slender, about 3 times as long as wide. Prozona almost as wide as metazona. Mesothorax similar to metathorax, simple, nearly trapezoidal. Thorax with distinct medial keel. Wingless.

Prothoracic legs: fore coxa smooth, unarmed, shorter than metazona; fore femur as long as coxa, with a strongly-developed genicular spur (Fig. 5B), 4 posteroventral, 4 discoidal, 15–16 anteroventral spines, and without dilation on dorsal surface (Fig. 5A,B); claw groove lying basally to middle of fore femur; fore tibia about half as long as femur, with 5–6 posteroventral, 10 anteroventral tibial spines and 1 strong tibial spur; fore tarsus longer than tibia; basal tarsomere (= basitarsus) longer than total length of remaining segments.

Meso- and metathoracic legs: slim without expansions and with one small femoral genicular spur and one obvious tibial spur. Tarsus much shorter than tibia; basal tarsomere short, less than total length of remaining segments. Metathoracic legs longer and stronger than mesolegs.

Abdomen: almost as wide as pronotum. Each abdominal segment similar, nearly square; tergite 10 (Supra-anal plate) broad, widely trianglar. Cerci possessing 15 joints, with distal joints gradually becoming longer distad. Each of last 3 joints longer than wide (Fig. 5E). Coxosternite 9 (subgenital plate) nearly triangular, slightly asymmetrical, with a pair of styli.

External genitalia (Fig. 6B, C): relatively large-sized. Left phallomere narrow and long, posterior process of ventral phallomere (spd) indistinct; phalloid apophysis (afa) short, wide and strongly sclerotized, with a spine-like projection; posterior process of left phallomere (paa) with a finger-like extension, with a small obtuse tubercle in middle, and with a brush-like cluster of hairs on base.

Female. Similar to male, but distinctly larger and stronger (Figs 1B, 5C).

Measurements (Length in mm, Holotype in parentheses). Body: male 28.30–28.75 (28.45), female 32.50–35.15; head: male 5.85–5.95 (5.94), female 7.45–7.55; pronotum: male 5.35–5.39 (5.39), female 6.95–7.10; fore coxae: male 3.13–3.18 (3.15), female 4.11–4.20; fore femora: male 4.10–4.13 (4.11), female 4.62–4.80; fore tibiae: male 2.25–2.30 (2.27), female 2.85–3.02; middle femora: male 4.42–4.51 (4.45), female 5.70–5.79; hind femora: male 6.20–6.27 (6.25), female 7.43–7.52; cercus: male 5.45–5.50 (5.47), female 7.30–7.35.

The new species is distinguished from D. lanceolata by small body size, small and indistinct male ocelli, wingless male adults, comparatively large-sized genitalia, ventral phallomere without secondary distal process (sdp), additional obtuse tubercle on paa and different structure of afa (Fig. 6).

(Figs 2, 3). Monotonous, tawny, dry-grass-like, densely covered with little black spots. Some specimens possessing irregular black patches. Spines of fore legs brown.

The new species often lives at the bottom of bushes in a variety of angiosperms (Figs 2, 3A–D) in high-altitude coniferous forest. Nymphs were found to be clustering (Fig. 3B), without cannibalism. This peaceful situation is an exception for mantis. The mating (Fig. 3D) is also peaceful, and needs up to 4–8 hours. Female lays their oothecae on the fifth day after mating. Oothecae are fusiform, withered-leaf-like. Each ootheca contains 4–10 eggs (Fig. 1D). Color of ootheca varies from light to very dark brown. External wall of cotheca is thin, sparse.Oothecae did not hatch successfully in the laboratory probably due to significant elevation differences from the mantis’s natural habitat. In field, the mantis species prey on small-sized insects (e.g., Diptera, Hemiptera and Collembola) (Fig. 3C), based on our observations.

China (Tibet: Gyirong County).

The new species was named after Bai Li, who is a poet in the Tang dynasty of China and one of the most famous poets in Chinese history.