Sericothripinae Karny 1921

Key to the genera and species of Sericothripinae from Saudi Arabia

1. Metasternal plate anterior margin with deep U- or V-shape invagination medially (Figs 2, 9)............. Hydatothrips... 2

- Metasternal plate anterior margin either transverse (Fig. 19) or with shallow emargination medially (Fig. 26)................................................................................................. Neohydatothrips... 3

2. Ocellar triangle closely striated (Fig. 1); metanotum longitudinally striate (Fig. 3); setal pair S3 on abdominal tergites IV–VI at posterior margin, with only three setae anterior to S3 (Fig. 4); tergite IX with three pairs of mid-dorsal setae (Fig. 5); abdominal segments IV–V yellow (Fig. 32)............................................................. H. adolfifriderici

- Ocellar triangle with widely spaced striae (Fig. 8); metanotum longitudinally reticulate (Fig. 10); setae S3 on abdominal tergites IV–VI placed far ahead of posterior margin, with 6–8 setae anterior to S3 (Fig. 11); tergite IX with two pairs of mid-dorsal setae (Fig. 13); abdominal segments reddish brown (Fig. 34)......................................... H. bahaensis sp. n.

3. Occipital apodeme confluent with posterior margin of compound eyes (Fig. 16), ocellar setae pair III arising at external margin of triangle and shorter than distance between their bases; metasternal plate with anterior margin transverse (Fig. 19); sternites without discal microtrichia or posteromarginal comb (Fig. 20); tergite IX with only one pair of mid-dorsal setae (Fig. 21); abdominal segments I–VI unicolor pale yellow to white, without trace of shadings (Figs 36, 37)................ N. amygdali

- Occipital apodeme widely spaced from posterior margin of compound eyes (Fig. 25), ocellar setae pair III arising inside the triangle and longer than distance between their bases; metasternal plate with anterior margin shallowly invaginated (Fig. 26); sternites with discal microtrichia and III–VI with postero-marginal comb (Fig. 29); tergite IX with two pairs of mid-dorsal setae (Fig. 30); abdominal segments largely brown, except tergites IV–V yellow medially (Fig. 38).............. N. samayunkur