Key to Phlaeothripinae genera associated with Casuarinaceae

1. Antennal segment VIII slender and sharply constricted to narrow basal pedicel (Fig. 77); antennal segment II with sensorium on basal half of segment; mouth cone pointed and extending to (or almost to) mesosternum (Fig. 74).......... Xyelethrips

-. Antennal segment VIII short with broad base; antennal segment II with sensorium usually on distal half of segment; mouth cone shorter, rarely extending across prosternum................................................................. 2

2. Antennal segment IV with 2 sense cones, III without sense cones (rarely with only 1); fore wing without duplicated cilia or micropterous......................................................................................... 3

-. Antennal segment IV with 3 sense cones (rarely with only 2), III with one sense cone; fore wing usually with duplicated cilia, rarely micropterous.................................................................................... 5

3. Antennal segment VI broadly truncate at apex, VII scarcely narrowed at base (Figs 2–9); maxillary stylets crossing over each other in head or at least touching medially (Figs 11–19)................................................ Adrothrips

-. Antennal segment VI with apex slightly narrowed, VII clearly narrowed to base (Fig. 72); maxillary stylets more widely separated............................................................................................ 4

4. Antennal segment III without sense cones; female abdominal segment IX without sclerotised fustis; postocular setae long in macropterae, short in micropterae.............................................................. Iotatubothrips

-. Antennal segment III with one sense cone; female abdominal segment IX with fustis well developed; post ocular setae always minute..................................................................................... Phallothrips

5. Fore femora of both sexes with row of tubercles on inner margin (Fig. 47)............................ Thaumatothrips

-. Fore femora never with row of tubercles on inner margin...................................................... 6

6. Head of females with inter-antennal projection about as long as antennal segment I (Fig. 40), males with this projection only half as long as antennal segment I................................................................ Akthethrips

- Head not produced between bases of antennal segments...................................................... 7

7. Head elongate, more than 1.5 times as long as wide (Fig. 44), with mouth cone acute, extending across prosternum; mesopresternum reduced to small median sclerite (Fig. 45); tergite II strongly eroded laterally; antennal segment II with sensorium on basal half of segment (Fig. 43); fore wing when present broad but without duplicated cilia and tergites without wing-retaining setae.................................................................... Enigmathrips gen.n.

-. Head wider than long, rarely more than 1.1 times as long as wide, mouth cone not extending across prosternum; mesopresternum transverse or reduced to two lateral triangles (Figs 64–66); tergite II complete laterally; antennal segment II with sensorium on distal half of segment; fore wing rarely absent, with duplicated cilia................................... Heligmothrips