Xistra Bolívar, 1887

Zhang, Rong-Jiao, Deng, Wei-An, Li, Jie-Juan & Lin, Li-Liang, 2022, Pygmy grasshoppers of the genus Xistra Bolívar, 1887 (Orthoptera: Tetrigidae: Metrodorinae), Zootaxa 5162 (2), pp. 183-197 : 185-187

Key to the species of Xistra Bolívar

1. Head in frontal view with vertex forming a “deep V”-shaped concavity ( Fig. 1A–B )................................ 2

- Head in frontal view with vertex forming a “U”-shaped concavity ( Fig. 1C )...................................... 14

2. “V”-shaped concavity deeper, bottom of which reaching middle of inner margins of eyes; in profile, upper margin of pronotum distinctly protruding before shoulders, behind forming a concavity....................... Xistra gogorzae Bolívar, 1887

- “V”-shaped concavity shallow, bottom of which reaching one-third to one-fifth of upper inner margins of eyes........... 3

3. Lower margins of fore and mid femora undulated............................................................ 4

- Lower margins of fore and mid femora straight.............................................................. 5

4. In profile, upper margin of pronotum undulating; lateral margins of vertex slightly exerted above upper margin of eyes; frontal costa concave between lateral ocelli.................................. Xistra lochengensis (Zheng, 2005) , comb. nov.

- In profile, upper margin of pronotum straight; lateral margins of vertex reaching the level of upper margin of eyes; frontal costa straight between lateral ocelli.................................................. Xistra hainanensis Deng , sp.nov.

5. In profile, upper margin of pronotum straight............................................................... 6

- In profile, upper margin of pronotum with 1–2 projections or slightly undulating before shoulders and straight behind shoulders................................................................................................ 8

6. Width of one eye 2.0 times width of vertex in male, posterior margin of subgenital plate of female straight................................................................................ Xistra brachynota Li, Deng & Zheng, 2014

- Width of one eye 1.0–1.5 times width of vertex in male, posterior margin of subgenital plate of female with a triangularly projecting in the middle................................................................................... 7

7. Width of one eye equal to width of vertex in male; antennae inserted far below lower margin of eyes; hind tibia black; ventral thorax and abdomen brown.............................................. Xistra nigritibialis Zheng & Jiang, 2002

- Width of one eye 1.5 times width of vertex in male; antennae inserted just below lower margin of eyes; hind tibia white; ventral thorax and abdomen black................................................... Xistra parvula Liang & Chen, 2010

8. In profile, upper margin of pronotum with one lamellate projection between shoulders; antennae inserted far below lower margin of eyes; ventral thorax and abdomen brown................................. Xistra foliolata Liang & Chen, 2010

- In profile, upper margin of pronotum with two projections or slightly undulating before shoulders and straight behind shoulders; antennae inserted slightly below or between lower margins of eyes; ventral thorax and abdomen black............. 9

9. Body large sized, length of body: ♂ 10.0– 10.5 mm, ♀ 13.0– 13.5 mm; posterior angles of lateral lobes of pronotum truncate and apex of posterior angles bearing triangular.................................... Xistra nigriabdominis Deng , sp. nov.

- Body small sized, length of body: ♂ 6.0– 7.6 mm, ♀ 7.5–10.5 mm; posterior angles of lateral lobes of pronotum truncate... 10

10. Lateral carinae of prozona constricted backward................................ Xistra strictivertex Zheng & Ou, 2010

- Lateral carinae of prozona parallel....................................................................... 11

11. Middle femora 1.3 times as wide as the visible part of tegmina in female; posterior margin of subgenital plate with three teeth............................................................. Xistra bannaensis Deng, Wang, Mao & Li, 2021

- Middle femora equal to or narrower than the visible part of tegmina in width in female; middle of posterior margin of subgenital plate triangular projecting.............................................................................. 12

12. Antennae inserted between lower margins of eyes; width of visible part of tegmen 1.4 times width of mid femur.................................................................................. Xistra cambodia Storozhenko, 2021

- Antennae inserted slightly below lower margins of eyes; width of visible part of tegmen equal to width of mid femur..... 13

13. In frontal view, vertex with V-shaped concavity, bottom of which reaching one- third of upper inner margins of eyes; anterior margin of pronotum concave in middle; hind tibia black, with two light rings in the middle.................................................................................................... Xistra nigrinota Zheng & Xu, 2010

- In frontal view, vertex with V-shaped concavity, bottom of which reaching one- fifth of upper inner margins of eyes anterior margin of pronotum truncate; hind tibia yellow......................... Xistra orchotibia Deng, Wang, Mao & Li, 2021

14. Width of an eye equal to width of vertex.................................................................. 15

- Width of an eye 1.5–2.0 times width of vertex.............................................................. 17

15. In frontal view, lateral margins of vertex slightly exerted above upper margin of eyes; lateral ocelli placed in between lower margins of eyes; hind tibia yellow brown............................................ Xistra laticorna Zheng, 1988

- In frontal view, lateral margins of vertex elevated up to the level of upper margin of eyes; lateral ocelli placed in the lower onethird of anterior margin of eyes; hind tibia with two or three black rings......................................... 16

16. Pronotum with a pair of interhumeral carinae between shoulders; ventral margins of middle femora undulated................................................................................... Xistra lativertex Zheng & Mao, 2010

- Pronotum without interhumeral carinae between shoulders; ventral margins of middle femora straight...................................................................................... Xistra longidorsalis Liang & Jiang, 2004

17. In profile, upper margin of pronotum straight or slightly protruding before shoulders; hind wing not reaching or reaching apex of hind pronotal process............................................................................... 18

- In profile, upper margin of pronotum with two hill-shaped bulges or comb shaped before shoulders; hind wing surpassing apex of hind pronotal process............................................................................... 21

18. Width of frontal ridge between antennae wider than antennal groove diamete; with a pair of interhumeral carinae between shoulders....................................................... Xistra guangxiensis ( Zheng, 1998) , comb. nov.

- Width of frontal ridge between antennae narrower than antennal groove diamete; interhumeral carinae absent between shoulders............................................................................................... 19

19. Lateral ocelli placed in between lower margins of eyes; hind tibia yellow brown........... Xistra medogensis Zheng, 2005

- Lateral ocelli placed in the lower one-third of anterior margin of eyes; hind tibia black............................. 20

20 In profile, upper margin of pronotum slightly protruding before shoulders; width of middle femora equal to width of the visible part of tegmina; ventral thorax and abdomen black......................... Xistra emeiensis ( Zheng, 1998) , comb. nov.

- In profile, upper margin of pronotum distinctly protruding before shoulders; width of middle femora distinctly narrower than width of the visible part of tegmina; ventral thorax and abdomen brown......... Xistra jiulianshanensis Zheng & Shi, 2009

21. In profile, upper margin of pronotum forming comb shaped before shoulders; lateral margin of frontal ridge upper narrower, lower broader; body surface with big tubercles..................................... Xistra longicornis Ingrisch, 2001

- In profile, upper margin of pronotum with two hill-shaped bulges before shoulders; lateral margin of frontal ridge nearly parallel; body surface with small particles..................................................................... 22

22. Lateral margins of vertex distinctly exerted before the upper margin of eyes; median carina of pronotum high, slightly lamellar.......................................................................... Xistra angusta Ingrisch, 2001

- Lateral margins of vertex reaching upper margin of eyes; median carina of pronotum low, not lamellar................. 23

23. Antennal grooves inserted far below inferior margins of compound eyes; interhumeral carinae between shoulders long and constricted backwards; middle of posterior margin of subgenital plate in female triangular projecting...................................................................................... Xistra wuyishanensis Zheng & Zeng, 2011

- Antennal grooves inserted just below inferior margins of compound eyes; interhumeral carinae between shoulders short and paralle; posterior margin of subgenital plate in female with three teeth.................... Xistra shilinensis Zheng, 2015

Figures

FIGURE 1A–C. Xistra gogorzae Bolívar, 1887; Xistra parvula Liang & Chen, 2010; Xistra guangxiensis (Zheng, 1998). A—Xistra gogorzae, frontal view of head (photo: Sigfrid Ingrisch); B—Xistra parvula, frontal view of head (after Liang & Chen); C—Xistra guangxiensis, frontal view of head (after Zheng).