Key to species of Lomachaeta (Males)

1. Ventral margin of mandible armed with strong tooth basally................................................... 2

- Ventral margin of mandible lacking tooth basally............................................................ 4

2(1). Femora and tegulae orange brown, contrasting with entirely black mesosoma and metasoma (Fig. 42; southwestern USA and northwestern Mexico)..................................................... L. cirrhomeris Pitts & Manley, 2004

- Femora and tegula usually blackish, mesosoma blackish, metasoma often partly reddened; if femora orange, then metasoma also predominantly orange (Figs 44–45)................................................................... 3

3(2). Penis valve with one basal tooth (see Pitts & Manley 2004, Fig. 16–18); body color variable, entirely black or with metasoma cuticle variably orange to red (Figs 43–46; widespread in Nearctic)............................ L. hicksi Mickel, 1936

- Penis valve with two basal teeth (see Pitts & Manley 2004, Fig. 14); body entirely black (Fig. 42; Nayarit, Mexico South to Costa Rica)............................................................. L. chionothrix Pitts & Manley, 2004

4(1). Metasoma largely red to orange (e.g. Figs 47–52; North America only).......................................... 5

- Body entirely black except tegula, head, or legs sometimes orange or lighter brown (Figs 53–64; North or South America). 9

5(4). Paramere broadly flattened throughout, rounded apically (Arizona, California, and Nevada; Fig. 47, also see Pitts & Manley 2004, Fig. 23).......................................................... L. beadugrimi (Pitts & Manley 2004)

- Paramere acuminate apically, at most laterally compressed (e.g. Pitts & Manley 2004, Figs 14–22).................... 6

6(5). Wing venation reduced, cells contained in basal half of forewing (Figs 48, 49); paramere lacking row of elongate setae ventrally (e.g. Fig. 67).................................................................................... 7

- Wing venation normal, cells extending beyond basal half of forewing (e.g. Fig. 52); paramere with somewhat uniform row of long setae ventrally (see Manley & Pitts 2004; Fig. 19, 20)................................................... 8

7(1). Head and mesosoma orange, concolorous with T2 (Fig. 49); paramere laterally compressed, moderately setose (Fig. 49, 50; Riverside County, California)................................................. L. calamondin Williams, sp. nov.

- Head and mesosoma black (Fig. 48); paramere not so compressed, basically subcylindrical, sparsely setose (Central Valley and Coast Ranges, California)....................................................... L. powelli (Mickel), 1964

8(7). Pronotum and mesoscutum with IS more than twice PD; metasoma blackish with orange color restricted to T2 and T3 (Fig. 51; Sonoran Desert in Arizona and California, USA and Oaxaca, Mexico)............ L. ptilohyalus Pitts & Manley, 2004

- Pronotum and mesoscutum with IS less than twice PD; metasoma mostly orange (Fig. 52; Great Basin to Chihuahuan Desert in southwestern Nearctic Region)............................................ L. crocopinna Pitts & Manley, 2004

9(7). Apical fringe of T2 with row of convergent thick bristles (e.g. Figs 53, 54, 57; North and South America).............. 10

- Apical fringe of T2 with simple setae only (e.g. Figs 58, 60, 63; North America).................................. 13

10(9). Vertex with separated punctures, IS=PD; paramere having long setae on external surface medially (see Williams & Pitts 20 0 9, Fig. 15; Sonora, Mexico)..................................................... L. theresa Williams & Pitts, 2009

- Frons and vertex coarsely punctate or areolate; paramere lacking long setae except sometimes at apex (South America)... 11

11(10). T1 shape nodose, anterior face convex (Fig. 56); apical third of paramere distinctly downcurved (Fig. 71; Colombia).................................................................................... L. juanita Williams, sp. nov.

- T1 shape disciform, anterior face flat or concave (Figs 53, 55); paramere basically straight or evenly downcurving throughout its length (e.g. Manley & Pitts 2004, Fig. 21).............................................................. 12

12(11). Gena weakly carinate, apex of paramere with weak tuft of long setae (see Williams & Pitts 2009, Fig. 7; Argentina, Brazil, and Paraguay)....................................................................... L. vianai Casal, 1969

- Genal carina distinct; apex of paramere lacking setal tuft (see Manley & Pitts 2004, Fig. 21; Northern South America)............................................................................. L. hyphantria Pitts & Manley, 2004

13(9). Paramere broadly flattened, rounded apically (Fig. 69; also see Williams & Pitts 2009, Fig. 13)..................... 14

- Paramere acuminate apically, at most laterally compressed (e.g. see Williams & Pitts 2009, Fig. 1)................... 15

14(13). Cuspis and paramere with all setae shorter than paramere width (see Williams & Pitts 2009, Fig. 13; Sonoran Desert in California)................................................................ L. snellingella Williams & Pitts, 2009

- Cuspis and paramere with setae much longer than paramere width (Figs 59, 69; Sonora, Mexico)................................................................................................... L. eironeia Williams, sp. nov.

15(13). Paramere lacking long setae, all setae shorter than paramere width (see Williams & Pitts 2009, Fig. 9; Arizona, USA and Sonora, Mexico).................................................... L. polemomechana Williams & Pitts, 2009

- Paramere with at least some ventral or apical setae longer than mid-paramere width............................... 16

16(15). Entire paramere with continuous ventral setal row (see Williams & Pitts 2009, Fig. 3; Mohave and Sonoran Deserts in California and Nevada)............................................................... L. ilex Williams & Pitts, 2009

- Long ventral setae of paramere absent from basal half....................................................... 17

17(16). Paramere narrow throughout, long cylindrical, apically convergent, and evenly curving ventrally throughout length (Fig. 63, also see Williams & Pitts 2009, Fig. 5; Arizona, USA and Sonora, Mexico)........... L. litosisyra Williams & Pitts, 2009

- Paramere evenly tapering toward apex, somewhat laterally compressed, subparallel, and virtually straight to apex or scarcely downcurving (e.g. Figs 62, 64)......................................................................... 18

18(17). Long setae of paramere restricted to tuft in apical fifth of free length (see Williams & Pitts 2009, Fig. 17; Texas, New Mexico, and Arizona, USA and Sonora, Mexico)..................................... L. vacamuerta Williams & Pitts, 2009

- Long setae of paramere scattered through apical half of free length (see Williams & Pitts 2009, Fig. 1; Baja California Sur, Mexico).................................................................. L. hedera Williams & Pitts, 2009