Key to Hydatothrips species

1. Ocellar triangle without sculpture lines; tergite IX of female with 3 pairs of mid-dorsal setae; metasternal plate with broadly U- shaped invagination...................................................................... williamsi comb. n.

-. Ocellar triangle with sculpture lines (Figs 3–8); tergite IX with either 2 or 4 pairs of mid-dorsal setae; metasternal plate invagi- nation not broadly U-shaped............................................................................ 2

2. Fore wing with three distinct pale bands; meso and metanotum with many microtrichia (Fig. 12)................ gliricidiae

-. Fore wing with one or two pale bands; meso and metanotum with no microtrichia.................................. 3

3. Anterior third of pronotum broadly reticulate (Figs 3, 5); tergite IX with 4 pairs of mid-dorsal setae; fore wing second vein with no setae......................................................................................... 4

-. Anterior third of pronotum transversely reticulate (Figs 4, 7, 8); tergite IX with 2 pairs of mid-dorsal setae; fore wing second vein with two setae.................................................................................... 5

4. Pterothorax brown; mesonotum transversely striate (Fig. 5), metanotum longitudinally striate.................. tricinctus

-. Pterothorax yellow, meso and metanotum conspicuously reticulate (Fig. 9)........................... canavaliae sp. n.

5. Transverse reticles on pronotum without internal markings (Fig. 7)..................................... guanacastei

-. Transverse reticles on pronotum with internal markings (Figs 4, 8)............................................... 6

6. Hind tibiae yellow; ocellar area without internal markings between striae; sternites with microtrichia medially...... sternalis

-. Hind tibiae brown; ocellar area with internal markings between striae; sternites without microtrichia medially....... volcano