Liothrips Uzel

Liothrips Uzel, 1895: 261 . Type species Phloeothrips setinodis Reuter, by subsequent designation of Hood, 1918: 131.

The earliest species of Liothrips recorded from China (Taiwan) were malloti, malloti var. flavicornis and terminaliae by Moulton (1928a), of which the first two are now treated as synonyms of L. brevitubus, and the third has been transferred to Liophloeothrips (Priesner 1968) (Wang & Lin 2020) . Additionally, Moulton (1928a; 1928b) described several species in Gynaikothrips from Taiwan, of which three are now placed in Liothrips, L. kuwayamai, L. takahashii and L. kuwanai, of which the latter was synonymised with L. pallipes by Mound (2020). Zhang studied thrips specimens collected from southern China, among which five valid species of Liothrips were recorded (Zhang 1984; Zhang et al. 1999). Finally, Han focused on southwest part of China, and described seven valid species (Han 1988, 1993, 1997a, 1997b). After that, no one tried to review this large genus across China, until 2020, when 12 species were recorded from Taiwan including two new species (Wang & Lin 2020). Based on the above studies, we here try to clarify the diversity of this genus in China including 33 species in total, of which five are known only from Taiwan (Table S1).

Generic diagnosis: Medium sized, usually dark and macropterous. Antennae 8-segmented, VIII much shorter than VII (Figs 31–40), and broad at base, III–IV with one and three major sense cones respectively (Figs 22–30, 41), IV rarely with two. Head length various, ranged from broader than long to about twice as long as wide (Figs 1–13, 15–21); usually transversely striate or weakly reticulate; usually with one pair of long postocular setae (rarely 2 or 0); eyes well-developed; maxillary stylets retracted halfway to postocular setae or eyes, close together or wide apart. Pronotum usually with 5 pairs of major setae (Figs 42–46, 49–52), sometimes am or aa or pa reduced (Figs 47, 48), rarely only epim developed, notopleural sutures complete; basantra absent, ferna large, mesopresternum transverse or divided into two triangles (Figs 53–58, 61–68); metathoracic sternopleural sutures usually well developed (Figs 66–68), rarely absent. Fore tarsal tooth absent in both sexes; fore wings not constricted medially, usually with many duplicated cilia. Pelta triangular (Figs 69–87), tergites II–VII each with 2 pairs of sigmoid wing-retaining setae; IX with setae S1 and S2 usually long and pointed (Figs 97–102); tube usually shorter than head, anal setae usually as long as tube or shorter. Male sternite VIII usually with large pore plate (Figs 91, 94–96), rarely small or absent, sometimes tergite VIII with a pair of pore plate as well (Figs 92, 93).

Key to Liothrips species of China

(* indicates species not seen; L. hsuae is excluded; L. mirabilis is included due to its pest potential of Piper plants grown throughout southern China.)

1. All legs brown (Fig. 60), sometimes paler at fore tibiae apices and tarsi.......................................... 2

-. At least all tarsi yellow (Fig. 59)......................................................................... 3

2. Postocular setae short, just reaching posterior margin of eyes (Fig. 3); metanotum with longitudinal reticulation (Fig. 76); antennal segments VII and VIII broadly joined (Fig. 35); major setae blunt at apices (on leaves of Picea sp.).... piceae sp. n.

-. Postocular setae about as long as or longer than eyes; metanotum with polygonal reticulation (Fig. 75); antennal segment VIII constricted at base; major setae with expanded apices (on leaves of Litsea glutinosa)......................... floridensis

3. All tibiae uniformly yellow............................................................................. 4

-. Mid and hind tibia at least more or less shaded.............................................................. 7

4. Postocular setae minute, not longer than other discal head setae (on Styrax sp.)............................ styracinus *

-. Postocular setae much longer than other discal head setae..................................................... 5

5. Pronotal pa setae minute (Fig. 48); metanotum finely reticulate (Fig. 73); tergite IX setae S1 short and blunt, about half length of S2 (Fig. 99)........................................................................... motuoensis sp. n.

-. Pronotal pa well developed, about as long as epim setae; metanotum closely striate; S1 on tergite IX acute, about as long as S2................................................................................................. 6

6. All major setae expanded or blunt at apex; postocular setae much shorter than eyes; tergite IX S1 setae shorter than tube; antennal segment III slender, about 4.0 times as long as wide (Fig. 27) (in leaf gall of Piper spp.)................. pallipes

-. All major setae acute at apex (Fig. 43); postocular setae slightly shorter than eyes (Fig. 10); tergite IX S1 setae longer than tube; antennal segment III slender, about 2.3 times as long as wide (Fig. 41) (on Pavetha hispida and in rolled leaf margins of pepper plant)......................................................................................... mirabilis

7. Head short, as long as wide or shorter..................................................................... 8

-. Head longer than wide................................................................................ 11

8. Postocular setae small, much shorter than eyes, just reaching posterior margin of eyes (Fig. 12) [fore wings hyaline] (on leaves of Populus euphratica)........................................................................ populi sp. n.

-. Postocular setae well developed, a little shorter than eyes or longer.............................................. 9

9. Metanotum closely striate (Fig. 71); antennal segments III–VI uniformly yellow (Fig. 23)................... brevis sp. n.

-. Metanotum longitudinally reticulate; antennal segments IV–VI more or less shaded brown.......................... 10

10. Fore wing hyaline; postocular setae much longer than eyes (Fig. 11) (on leaves of Adinandra millettii)..... longistylus sp. n.

-. Fore wing shaded brown; postocular setae a little shorter than eyes (on leaves of Symplocos laurina)............. aporosae

11. Proscutum eroded laterally, midlateral setae arising on the area of chitinous islets, pa minute [metanotum closely striate (Fig. 70)] (on leaves of Tsuga chinensis)............................................................. bournierorum

-. Proscutum fully transverse bearing midlateral setae laterally, pa setae elongate.................................... 12

12. Front part of pronotum (Fig. 50), metanotum (Fig. 84) and lateral parts of tergites II–VII distinctly reticulate [Antennal segments III–VI uniformly yellow, VII–VIII brown (Fig. 39); mid and hind tibiae uniformly brown; S1 on tergite IX blunt, shorter than S2 (Fig. 101)]............................................................................. tibetanus sp. n.

-. No reticulation on lateral parts at least of tergites II–VII...................................................... 13

13. Fore tibiae more or less shaded, at least basally or exteriorly.................................................. 14

-. Fore tibiae clear yellow............................................................................... 24

14. Tergite II close to lateral margin with irregular row of 9–12 discal setae......................................... 15

-. Tergite II close to lateral margin with irregular row of 4–7 discal setae.......................................... 16

15. Head twice as long as wide (Fig. 3); antennal segment III about 5 times as long as wide (Fig. 31); postocular setae scarcely reaching posterior margin of eyes (Fig. 3); pronotal setae am and aa small (Fig. 45), sometimes well-developed in male (on leaves of Ficus tikoua)..................................................................... elongatus sp. n.

-. Head 1.4 times as long as wide (Fig. 20); antennal segment III about 3 times as long as wide; postocular setae extending wellbeyond posterior margin of eyes (Fig. 20); pronotum with strong and dark major setae, am and aa usually developed................................................................................................... takahashii

16. Postocular setae far from eyes, located dorsally in middle of head (Fig. 8); pronotal setae am minute, much shorter than ml (Fig. 46)................................................................................................ 17

-. Postocular setae close to eyes; pronotal am and aa well developed, sometimes reduced............................. 18

17. Mid and hind tibiae brown in basal half, yellow in apical half; pronotal aa setae as minute as am (Fig. 46) (on Globba racemosa)................................................................................... mohanrami

-. Mid and hind tibiae uniformly brown; pronotal aa setae much longer than am (on Liquidambar sp.)........... threobrevis *

18. Fore wings hyaline................................................................................... 19

-. Fore wing shaded brown or grey, at least with a dark stripe................................................... 20

19. Mesopresternum reduced to two lateral triangles; antennal segment III yellow, IV–VI yellow with shaded apices (Fig. 22) (on Gnetum spp.)................................................................................ adusticornis

-. Mesopresternum boat-shaped with median protrusion; antennal segments III–VI uniformly yellow, sometimes VI shaded at apices (on Viburnum sp.)...................................................................... kuwayamai *

20. Antennal segments III–VII yellow except VII brownish at apex, VIII brown; mid and hind tibiae uniformly dark brown... 21

-. Antennal segments VII–VIII brown; apical 1/6–1/3 of mid and hind tibiae yellow................................. 22

21. Postocular setae shorter than eyes; antennal segments III–IV slender and elongate, III longer than IV (Fig. 24) (in leaf galls of Fagraea obovata)............................................................................... fagraeae

-. Postocular setae longer than eyes; antennal segments III–VII short, III slightly shorter than IV (on Mallotus sp.)... brevitubus

22. Metanotum sculptured with hexagonal reticles medially............................................. dayulingensis *

-. Metanotum sculptured with narrow reticulation or longitudinal stripes medially................................... 23

23. Postocular setae blunt or expanded at apex (Fig. 7); antennal segments slender, III about 3.0 times as long as wide, IV about 2.2 times as long as wide, sense cones on III–IV as long as or a little longer than width of their segments (Fig. 37); metanotum with narrow reticulate sculpture (Fig. 83); anal setae shorter than tube (on Gentiana scabra)................... miyazakii

-. Postocular setae acute at apex (Fig. 18); antennal segments short and broad, III about 2.0 times as long as wide or a little longer, IV about 1.5 times as long as wide (Fig. 40), sense cones on III–IV no longer than width of their segments; metanotum sculptured with complete and dense longitudinal stripes medially but at anterior angles scarcely narrowly reticulate (Fig. 85); anal setae about as long as tube (on lily bulbs)....................................................... vaneeckei

24. Pelta with no CPS, with or without small setae posterolaterally................................................ 25

-. Pelta with a pair of CPS, sometimes with a minute seta close to the CPS......................................... 26

25. Pelta with 3–4 small setae posterolaterally (Fig. 72); antennal segments IV–VI uniformly yellow, VII–VIII brown (Fig. 36) (on leaves of Schefflera heptaphylla)............................................................. heptapleuricola

-. Pelta without any small setae; antennal segments IV–VIII yellow, sometimes VIII slightly shaded (on Vitex sp.).... vitivorus *

26. Head short, no more than 1.3 times as long as wide; antennal segment III no more than 3 times as long as wide.......... 27

-. Head elongate, more than 1.5 times as long as wide; antennal segment III more than 3 times as long as wide............ 28

27. Antennal segments III–VIII uniformly yellow except VIII slightly shaded (Fig. 26); postocular setae shorter than eyes; fore wings hyaline (in leaf gall of Jasminum grandiflorum).................................................... minys

-. Antenna segments IV–V shaded at apex, VI brown with pale at base, VII–VIII uniformly brown (Fig. 34); postocular setae as long as eyes (Fig. 19); fore wings more or less shaded brown, with a longitudinal brown stripe (on leaves of Periploca sepium)....................................................................................... wasabiae

28. Sense cones on antennal segments III–IV short, shorter than width of this segment; metanotum longitudinally reticulate... 29

-. Sense cones on antennal segments III–IV elongate, longer than width of this segment; metanotum closely striate......... 30

29. Mid and hind tibiae yellow at apical and basal 1/5.................................................... bomiensis

-. Mid and hind tibiae uniformly dark brown (on leaves of Heptapleurum sp.)............................ heptapleurinus *

30. Sense cones on antennal segments III–IV elongate, longer than half the length of this segment (Fig. 28) (in leaf galls of Smilax glaucochina)................................................................................... piperinus

-. Sense cones on antennal segments III–IV shorter than half the length of this segment.............................. 31

31. Pronotal am and aa minute, sometimes aa a little longer but much smaller than ml (Fig. 47) (on leaves of Viburnum sieboldii)................................................................................................ hagai

-. Pronotal am and aa setae well developed (Fig. 49).......................................................... 32

32. Metathoracic sternopleural sutures absent; sense cones on antennal segments III–IV moderately long, about 1/2 times as long as this segment (Fig. 33) (on leaves of Rohdea japonica)................................................. rohdeae

-. Metathoracic sternopleural sutures present; sense cones on antennal segments III–IV short, about 1/3 times as long as this segment (Fig. 30)............................................................................... setinodis