Key to New World species of Adelius Haliday

1. Vein r present, although usually short, veins 2RS and 3RSa connected to each other but not to the stigma (Figs 11, 43, 69, 7 7).................................................................................................... 2

- Vein r absent, veins 2RS and 3RSa apart from each other and directly connected to stigma (Figs 6, 15, 22, 30, 85, 97)...... 8

2(3). Metapleuron, propodeum and hind coxae smooth and polished (Figs 1, 3, 73)...................................... 3

- Metapleuron sculptured, at least partly striate or rugose (Fig. 48, 112); and/or propodeum rugose (Fig. 41, 47); and/or hind coxae rugose dorsally (Fig. 53)........................................................................... 4

3(2). Hind tarsi and flagellum entirely brown (Fig. 1); anterior part of propodeum with one pair of lateral carinae (Fig. 3) (Costa Rica).................................................................................. A. adeleae sp. n.

- Hind basitarsus and tarsomere 5 brown, contrasting to whitish yellow tarsomeres 2–4, flagellum brown apically, basal 2–3 flagellomeres yellow (Fig. 65); anterior part of propodeum with one pair of lateral carinae plus one pair of sub-median carinae (Fig. 66) (Costa Rica)...................................................................... A. gauldi sp. n.

4(2). Wings hyaline (Fig. 11) (Bolivia)......................................................... A. boliviensis sp. n.

- Wings banded or entirely infuscate, sometimes weakly so (Figs 39, 77, 105)....................................... 5

5(4). Wings entirely infuscate (Fig. 39)......................................................................... 6

- Wings banded (Fig. 77) (Brazil).......................................................................... 7

6(5). Face with mid-longitudinal carina (Fig. 40); frons densely punctate (Fig. 42); legs entirely dark brown (Fig. 40) (Ecuador)...................................................................................... A. ecuadoriensis sp. n.

- Face without carina (Fig. 54); frons smooth and polished (Figs 51, 55); legs usually with distinct but narrow yellow bands at base of all femora (Fig. 49) (Colombia)....................................................... A. excelsus sp. n.

7(5). Head and mesosoma black (Fig. 76)......................................................... A. monteiroi sp. n.

- Head and mesosoma honey yellow (Fig. 105)............................................... A. sancticaroli sp. n.

8(1). Wings hyaline (Figs 85, 88)............................................................................. 9

- Wings banded, frequently only faintly so (Figs 71, 97). Doubtful species are keyed both ways (Fig. 15)................ 12 9(8). Propodeum mostly polished, anterior aspect about twice as long as posterior aspect (Fig. 89) (U.S. A)............................................................................................. A. nigripectus Muesebeck (in part)

- Propodeum rugose, anterior aspect less than twice as long as posterior aspect (Fig. 10, 20, 83) (Neotropical species)...... 10

10(9). Mesonotum and propodeum black (Figs 82, 83) (Brazil)..................................... A. morretesiensis sp. n.

- Mesonotum and propodeum light brown to honey yellow (Figs 5, 14)........................................... 11

11(10). Antenna brown apically; tibia without subbasal white bands (Fig. 14); face rugulose (Fig. 16) (Brazil).................................................................................................. A. caatinga sp. n. (in part)

- Antenna entirely yellow; all tibiae with a subbsal white band (Fig. 5); face transversely striate (Fig. 7) (Colombia)............................................................................................ A. bolivariensis sp. n.

12(8). Mesosoma including propodeum yellow (Figs 14, 74, 75)..................................................... 13

- Mesosoma with dark brown markings to mostly dark brown (Figs 29, 52, 64, 95).................................. 14

13(12). Sternaulus finely crenulate (Fig. 19); head mostly areolate-rugulose (Fig. 17) (Brazil).......... A. caatinga sp. n. (in part)

- Sternaulus smooth (Fig. 75); head mostly smooth and polished (Fig. 71) (Costa Rica).................... A. janzeni sp. n.

14(12). Metapleuron and gena mostly smooth and polished (Figs 95, 103).............................................. 15

- Metapleuron rugose or rugose-costate (as in figure 112); gena usually imbricate or aciculate (Fig. 38).................. 16

15(14). Hind coxa and metasoma dark brown (Fig. 92).............................................. A. panamensis sp. n.

- Hind coxa yellow, metasoma brown with T2+3 white (Fig. 101)................................... A. quiteriae sp. n.

16(14). Scutellum centrally smooth and mostly devoid of setae, with scattered setae only along lateral margins, sometimes also posterior part of mesoscutum (Fig. 25)........................................................................ 17

- Scutellum punctate, evenly and rather densely setose (Figs 29, 98).............................................. 18

17(16). Head with gena receding directly behind eyes—maximum width of head at mid-height of eyes (Fig. 87); head and mesonotum yellow (Fig. 86) (U.S.A.).................................................... A. nigripectus Muesebeck (in part)

- Head with gena not receding, distinctly convex—maximum width of head at gena (Fig. 24); body mostly reddish brown (Fig. 22) (Canada)......................................................................... A. canadensis sp. n.

18(16). Propodeum with distinct, roughly pentagonal areola, covering most of its length and not bisected by transverse carina (Fig. 100) (Costa Rica).................................................................... A. pentagonalis sp. n.

- Propodeum without pentagonal areola, if areola present then bisected by strong transverse carina (Figs 54, 63)........... 19

19(18). Ovipositor sheaths narrow and acute apically (Fig. 56); hind tarsi whitish yellow except tarsomere 5 brown (Fig. 52); first flagellomere 2.5× longer than apical width, apical flagellomere very short and nearly circular; head yellow with distinct concentric striation at frons and vertex (Fig. 55) (eastern U.S. A)................................ A. fasciipennis (Rohwer)

- Ovipositor sheaths wider, rounded or lanceolate apically (Figs 26, 59); hind tarsi brown or dark brown (Figs 34, 36, 65); first flagellomere less than 1.6× longer than apical width, apical flagellomere longer and with short pointed apex; head usually darker, if yellow, then without concentric striations dorsally................................................... 20

20(19). Vertex partly to entirely striate; maxillary palpi with apical segment pale brown, sometimes entirely dark brown; T1 with deep and well defined mid-basal sulcus, sometimes areolate rugose (Fig. 33); color extremely variable, from nearly entirely black to mostly yellow with brown propodeum (Figs 34, 36) (Western USA, associated with nepticulid leafminer mostly on Rhamnaceae and Quercus spp.)............................................................ A. coloradensis Muesebeck

- Vertex entirely covered with finely areolate-rugulose sculpturing (Fig. 62); maxillary palpi white (Fig. 60); T1 with shallow mid-basal sulcus (Fig. 63) (Florida, USA, associated with nepticulid leafminer on Hypericum sp.)....... A. floridensis sp. n.