Key to New World genera of Odiniidae

Following is a key to all odiniid genera in the New World. Nearctic genera not known from the Neotropical Region are indicated with brackets []. The two species of Helgreelia, gen. nov., are also differentiated in the key.

1. Posterior ocelli in front of line between medial vertical setae; ocelli usually arranged in isosceles tri- angle with distance between posterior pair conspicuously less than between either posterior ocellus and anterior ocellus; frons usually relatively arched (sometimes conspicuously tuberculate); scutel- lar disc sometimes setulose; in profile, face and frons more or less in line or sloping; TRAGINOPI- NAE.....................................................................................................................................................3

- Posterior ocelli in line with medial vertical setae; ocelli arranged in equilateral triangle or with dis- tance between posterior pair greater than between either posterior ocellus and anterior ocellus; frons flat to slightly concave; scutellar disc bare; in profile, face distinctly angulate with frons at antennal insertion; ODINIINAE ........................................................................................................................2

2 (1). Postocellar setae reduced, short and thin; dorsocentral setae 4 (1+3); anepisternum with 1–2 strong setae plus several setulae; dorsal preapical tibial setae well developed ..... [ Neoalticomerus Hendel]

- Postocellar setae well developed, subequal to ocellar setae; dorsocentral setae 5 (1+4); anepisternum bare; dorsal preapical tibial setae thin, hair-like ...................................... Odinia Robineau-Desvoidy

3 (1). Frons lacking enlarged tubercle, but occasionally with ocelli on raised bump which is little larger than diameter of anterior ocellus.........................................................................................................6

- Ocelli on moderately large to large tubercle, well in front of vertex..................................................4

4 (3). Arista long plumose; vein M1 strongly curved anterad at apex ........................ Paratraginops Hendel

- Arista pubescent; vein M1 straight......................................................................................................5

5 (4). Propleuron bearing 2 setae .................................................................................. Neotraginops Prado

- Propleuron lacking setae ...................................................................................[ Traginops Coquillett]

6 (3). Genal seta absent; costal vein extended to vein R4+5 or slightly beyond (Figs. 3 A, 3C) ................... 9

- Genal seta present; costal vein extended to vein M1 (Fig. 3 B) .......................................................... 7

7 (6). Scutellum at most bearing 2–5 setulae along margin .......................................... Lopesiodinia Prado

- Scutellar disc and margins bearing numerous setulae ....................................................................... 8

8 (7). Only anterior fronto-orbital seta inclinate ........................................................ Schildomyia Malloch

- Several anterior fronto-orbital setae inclinate (Fig. 2 C) ........................... Neoschildomyia, gen. nov.

9 (6). Postocellar setae present; posterior part of head straight from dorsal view (Fig. 2 E) ..........................

............................................................................................................................. Pradomyia gen. nov. - Postocellar setae absent; posterior part of head concave from dorsal view (Fig. 2 A) .....................10 10 (9). Several anterior fronto-orbital setae inclinate; scutellar disc setulose .................... Shewellia Hennig

- With single inclinate fronto-orbital seta (Fig. 2 A); scutellar disc bare .... Helgreelia, gen. nov. …. 11

11 (10). Abdomen orange, with fine pale setulae (Fig. 1 A, inset) ...................................... H. albeto, sp. nov.

- Abdomen grey and brown pruinose, with black setulae (Fig. 1 B, inset) .............. H. parkeri, sp. nov.