Key to species of Athlia (based on Saylor 1946b; Gutiérrez 1949; Martínez 1967, 1974)

1. Metathoracic wings reduced and non-functional (slightly lift an elytron to check). Central Chile (VIII Región del Biobío to IX Región de la Araucanía) (Fig. 69)..................................................... Athlia plebeja Burmeister

- Metathoracic wings full sized and functional................................................................ 2

2. Pronotum with basal angles evenly rounded, not protruding or angulate (Figs. 30, 34, 46)............................ 3

- Pronotum with basal angles protruding or angulate (Figs. 13, 17, 22, 26, 42, 52).................................... 5

3. Length less than 10 mm. Metatarsomere 1 noticeably shorter than metatarsomere 2 (Fig. 32). Southern Argentina (Neuquén to Chubut, Fig. 69)................................................................... Athlia parvissima Saylor

- Length greater than 10 mm. Metatarsomere 1 equal to or slightly shorter than metatarsomere 2 (Fig. 28)................. 4

4. Labrum weakly curved, weakly elevated medially; lateral border of clypeus slightly reflexed; dorsal surface tan to chestnut brown. Central Chile (V Región de Valparaíso, Fig. 79)................................... Athlia rotundata Gutiérrez

- Labrum evenly curved and elevated medially; lateral border of clypeus strongly reflexed; dorsal surface light brown to light tan. Southern Argentina (Neuquén to Chubut) and southern Chile (Región de Aisén, Fig. 68).......... Athlia giaii Martínez

5. Labrum not reflexed, on the same plane as clypeal surface. Southeastern Brazil (Santa Catarina, Fig. 67).................................................................................................... Athlia brasilica Saylor

- Labrum reflexed above the plane of clypeal surface........................................................... 6

6. Pronotum surface with dense, even punctures (Figs. 22, 42, 52)................................................. 7

- Pronotum surface with sparse, sometimes unevenly distributed punctures (Figs. 13, 26).............................. 9

7. Elytra evenly covered with setae; pronotum with long setae along lateral edges. Central Chile (IV Región de Coquimbo to IX Región de la Araucanía, Fig. 72)........................................................ Athlia rustica Erichson

- Elytra glabrous medially and sparsely setose laterally and apically; pronotum with long setae along lateral edge but mainly in apical half........................................................................................... 8

8. Elytra length less than twice the length of head and pronotum combined Northern and central Argentina (Jujuy to Río Negro, Fig. 67).............................................................................. Athlia bruchi Moser

- Elytra length greater than twice the length of head and pronotum combined. Central Chile (IV Región de Coquimbo to Región Metropolitana de Santiago, Fig. 70)................................................ Athlia problematica Gutiérrez

9. Length greater than 12 mm; apical and basal pronotal angles well developed (Fig. 26). Southern Brazil (São Paulo, Fig. 67)...................................................................................... Athlia freyi Martínez

- Length less than 12 mm; apical and basal pronotal angles weakly developed (Fig. 13). Northeastern Argentina (Buenos Aires, Fig. 67)............................................................................ Athlia bollei Martínez