Key to genera and species of Phlaeothripidae from Saudi Arabia

1. Maxillary palpi 2-segmented; maxillary stylets broad (5–10 µm); setae S2 on tergite IX as long as S1 and S3; antennal segments III–IV each with 2 sense cones (rarely one on segment III)[No specimens examined]....................... Heptathrips

-. Maxillary palpi 3-segmented; maxillary stylets not broad (2–3 µm, rarely 3–6 µm); setae S2 on tergite IX smaller than S1 and S3; sense cones on antennal segments III–IV various......................................................... 2

2. Abdominal segments III–VI without wing-retaining setae (Fig. 21); antennal segment IV with 1–2 sense cones (Figs 5–6); apterous species……………………….................................................................... 3

-. Abdominal segments III–VI with at least one pair of wing-retaining setae (Figs 20, 22–23); antennal segment IV with at least three sense cones (Figs 2–4, 7–11); wings usually present..................................................... 4

3. Antennae 7-segmented; segment III without sense cones, IV with only one; segments VI–VII broadly joined, VII not pedicilate at base (Fig. 6); maxillary bridge absent; major setae reduced and broad (Fig. 21); body sculptured............ Idiothrips

-. Antennae 8-segmented; segment III with one cone, IV with two; segments VI–VII, not broadly joined, VII pedicilate (Fig. 5); maxillary bridge present; major setae developed but not broad...................................... Apterygothrips

4. Antennal segment III slender, 4–5 times as long as wide (Figs 2–4); head elongate (Figs 12–17)...................... 5

-. Antennal segment III short, 1.2–2 times as long as wide (Figs 10–11); head not elongate (Fig. 38)..................... 8

5. Tube elongate, more than 6 times as long as basal width (Fig. 26); basantra absent; large species, body length more than 5000 microns (Figs 35, 49)........................................................................ Gigantothrips

-. Tube about 2.1 times as long as basal width (Figs 24–25); basantra present (Fig. 14) or absent (Fig. 17); medium sized species, maximum body length 3400 microns (Figs 47–48).......................................................... 6

6. Mouth cone short, not reaching fore coxae (Fig. 16); basantra absent (Fig. 17); metanotum with medium to compact cells of reticulation; segment IX with SI setae shorter than tube (Fig. 27)......................................... Liothrips

-. Mouth cone pointed and extending between the fore coxae (Fig. 12–14); basantra present (Fig. 14); metanotum with longitudinal striation (Figs 18–19); segment IX with SI setae longer than tube (Figs 24–25).................................... 7

7. Abdominal tergites with two pairs of wing-retaining setae, sometimes with accessory wing-retaining setae; apex of antennal segments IV–VI or VII symmetrical (Fig. 4), segment III with three well developed sense cones (Fig. 4); metanotum with few longitudinal striae (Fig. 19); hind margin of fore wing with duplicated setae............................. Dolichothrips

-. Abdominal tergites with more than two pairs of wing-retaining setae (Fig. 20); apex of antennal segments IV–VI or VII strongly asymmetrical (Fig. 3), segment III with one well developed sense cone (Fig. 3); metanotum very closely striate (Fig. 18); hind margin of fore wing without duplicated setae...................................................... Dolicholepta

8. External apical margin of fore femora recurved, with a small tooth-like projection; fore legs stout (Fig. 51).... Chiraplothrips

-. External apical margin of fore femora not recurved, without tooth; fore legs normal................................. 9

9. Abdominal segments III–VI with one pair of wing-retaining setae well-developed, rarely two (Fig. 29); fore wings weakly constricted medially........................................................................... Plicothrips

-. Abdominal segments III–VI always with two pairs of wing-retaining setae well-developed (Fig. 28); fore wings clearly constricted medially.......................................................................... Haplothrips