Key to species of Aegopsis Burmeister, 1847

(Male key modified from Dechambre & Grossi 1990)

1. Head and pronotum with horns, pronotal horn reduced in minor specimens (e.g., Figs 1 A–B, 9A–B, 10A–B) (males)..... 2

- Head and pronotum without horns (e.g., Figs 1C, 9C, 10C) (females)............................................ 7

2. Protibia with four external teeth, basal tooth sometimes reduced. Pronotum with disc strongly convex in major males................................................................................. A. curvicornis Burmeister, 1847

- Protibia with three external teeth. Pronotum with disc slightly convex............................................ 3

3. Base of cephalic horns connected by a curved carina. Lateral carina of parameres not reaching apex of parameres in lateral view......................................................................... A. peruvianus Arrow, 1941

- Base of cephalic horns with no connecting carina. Lateral carina of parameres reaching apex of parameres in lateral view.. 4

4. Apex of parameres less than one time longer than base of parameres (Fig. 12A). Mentum round (Fig. 12B)........................................................................................ A. chaminadei Dechambre, 1999

- Apex of parameres about two times longer than base of parameres (Fig. 6C, F, I). Mentum subrectangular or subtriangular (Fig. 5D, E, F)....................................................................................... 5

5. Clypeus with round apex (Fig. 2C). Ocular canthi protruding anteriorly (Fig. 3C). Apical corners of mentum carinate (Fig. 5E)................................................................. A. diceratops Sobral & Grossi, new species

- Clypeus apex truncate or slightly emarginate (Fig. 2A, E). Ocular canthi not protruding (Fig. 3A, E). Mentum lacking carina (Fig. 5D, F).......................................................................................... 6

6. Punctures on posterior angles of pronotum with no micropunctures between them (Fig. 2B). Mandibles with apical protuberance near external carina (Fig. 5A). Mentum subrectangular (Fig. 5D). Parameres, in lateral view, narrower than apex of phallobase (Fig. 6A)........................................................... A. bolboceridus (Thomson, 1860)

- Punctures on posterior angles of pronotum with micropunctures between them (Fig. 2F). Mandibles with no apical protuberance (Fig. 5C). Mentum subtriangular (Fig. 5F). Parameres, in lateral view, almost as thick as apex of phallobase (Fig. 6G)................................................................ A. vazdemelloi Sobral & Grossi, new species

7. Protibia with four external teeth, basal tooth sometimes reduced...................... A. curvicornis Burmeister, 1847

- Protibia with three external teeth......................................................................... 8

8. Ocular canthi round, canthi apex posteriorly almost indistinct. Galea triangular, apex recurved.. A. peruvianus Arrow, 1941

- Ocular canthi convex, canthi apex posteriorly distinct. Galea trapezoidal, apex straight.............................. 9

9. Clypeus trapezoidal (Fig. 7C). Frons with two strong tubercles (Fig. 7D). Punctures absent on disc of vertex (Fig. 7C)....................................................................... A. diceratops Sobral & Grossi, new species

- Clypeus round (Fig. 7A, E). Frons with two inconspicuous tubercles (Fig. 7B, F). Punctures present on disc of vertex (Fig. 7A, E)................................................................................................ 10

10. Vertex with deeper and coalescent punctures (Fig. 7E). Distance from canthi carina to canthi apex longer than canthi thickness. Sensorial area of maxillary palpi rugose (Fig. 4I)........................ A. vazdemelloi Sobral & Grossi, new species

- Vertex with shallower and annular punctures (Fig. 7A). Distance from canthi carina to canthi apex subequal to canthi thick- ness. Sensorial area of maxillary palpi striate (Fig. 4C)............................ A. bolboceridus (Thomson, 1860)