Key to Neohydatothrips from Australia

1. Body and wings largely pale, abdominal tergites II–VII with variably brown antecostal ridges and brown lateral areas, pronotal blotch light brown ............................................................................................................................... 2

-. Either the wings or the body sharply bicoloured or largely brown (Fig. 41, 73) ........................................................ 3

2. Sternites IV–VI with discal microtrichia complete across sternite, posterior margins with long microtrichia between each marginal seta (Fig. 53); mouth cone extending between fore coxae; male not known; on Sida leaves ................. .................................................................................................................................................................. N. gracilipes

-. Sternites IV–VI with no discal microtrichia mesad of marginal setae S2, and no marginal microtrichia except lateral to S3 (Fig. 40); mouth cone exceptionally long, extending to metasternum (Fig. 37); male not known ....................... .............................................................................................................................................................. N. barrowi sp.n.

3. Forewing with strongly contrasting brown and white bands, extreme apex paler than sub-apical shaded area (Fig. 73) ................................................................................................................................................................................ 4

-. Forewing not strongly banded, but sub-basal area pale before median darker area and sometimes with indistinctly paler area before dark apex .......................................................................................................................................... 6

4. Antennae 7-segmented (Fig. 68); mesonotum with median and submedian pairs of setae almost in transverse straight line (Fig. 69); male with large transversely oval glandular area on sternites III–VII (Fig. 67); on Ipomoea aquatica leaves ...................................................................................................................................................... N. plynopygus

-. Antennae 8-segmented; mesonotum with submedian pair of setae arising well posterolateral to median pair (Fig. 75); male without sternal glandular areas on III–VI.................................................................................................... 5

5. Body largely brown, pronotal anterior area yellow, median abdominal segments bicoloured (Fig. 73); tibiae and femora brown with apices yellow; abdominal sternites discal area covered with microtrichia, posterior margins with long fringe (Fig. 76); ocellar setae pair III on anterior margins of ocellar triangle (Fig. 74); three pairs of postocular setae, median pair elongate; occipital apodeme well separated from eyes; on Tagetes ........................ N. samayunkur

-. Body largely whitish yellow (Fig. 41), but dark brown on anterior part of head, meso and metanota, metasternum, tergites VII–VIII and lateral areas of tergite III; legs pale; sternites without microtrichia on disc and posterior margins; ocellar setae pair III arise between hind margins of posterior ocelli; two or three pairs of postocular setae; occipital apodeme confluent with eyes ................................................................................................... N. bellisi sp.n.

6. Ocellar setae III clearly anterolateral to ocellar triangle (Fig. 70); tergites II–VI posterior margin with fringe of microtrichia medially (Fig. 72); metasternum anterior margin forming a shallow broad V-shape (Fig. 71) .. N. poeta

-. Ocellar setae III within ocellar triangle (Fig. 46); tergites II–VI posterior margin without fringe of microtrichia medially (Fig. 48); metasternum anterior margin only weakly emarginate (Fig. 49); forewings with sub-apical lobe (Fig. 51); on leaves of various Fabaceae .................................................................................................................... 7

7. Metanotal reticulation almost equiangular, with internal linear markings (Figs 47, 50); male with no sternal glandular areas ........................................................................................................................................................... N. diana

-. Metanotal sculpture linear, with internal dot-like markings (Figs 61, 64); male with transverse glandular area on sternites V–VII (Fig. 65).............................................................................................................................................. 8

8. Mouth cone extending to mesosternum (Fig. 66); pronotal dark area with posterior margin deeply emarginate, posteromedian discal setae arise behind blotch (Fig. 63); metanotum sharply pale on posterior third (Fig. 64); tergites IV–V medially with few discal microtrichia; sternites V–VII with microtrichial fields not extending mesad of S2 ... ......................................................................................................................................................... N. katherinae sp.n.

-. Mouth cone extending to fore coxae; pronotal dark area with posterior margin weakly concave, posteromedian discal setae arise on blotch (Fig. 59); metanotum brown on posterior third; tergites IV–V medially with many discal microtrichia; sternites V–VII with microtrichia fields extending to setae S1(Fig. 62) .................................. N. haydni