Key to Metadorcinus species

1 Elytra with scattered yellowish-white tufts of scale-like setae......................... M. signatipennis (Deyrolle)

1’ Elytra without scale-like setae ..................................................................................................................... 2

2 Dorsal color reddish-brown, with black spots on pronotum and elytra....................................................... 3

2’ Dorsal color black or reddish-brown, uniform, or with lighter areas on humeri and elytral apex .............. 5

3 Discal interstriae carinate, male mandibles without vertical tooth … M. plagiatus (Burmeister)

3’ Discal interstriae flat, male mandibles strongly curved inwards with a strong medial tooth directed inwards and slightly upwards ..................................................................................................................... 4

4 Male head distinctly transverse; right paramere with an externally curved, basally concave ventral projec- tion (Fig. 18). Female striae represented by 7 longitudinal lines of simple punctures, interstriae dull......... .............................................................................................................................. M. cruentus (Burmeister)

4’ Male head not distinctly transverse, just subquadrate; right paramere with the ventral projection not strongly curved outwards and base convex (Fig. 17) (female unknown) ..................... M . auritus Kriesche

5 Elytral interstriae carinate............................................................................................................................ 6

5’ Elytral interstriae flat ................................................................................................................................. 10

6 Dorsal surface shiny..................................................................................................................................... 7

6’ Dorsal surface opaque................................................................................................................................ 9

7 Male pronotum anteromedially with a large, bifurcate projection (female unknown).................................. .................................................................................................................................... M. beneshi (Martínez)

7’ Male pronotum anteromedially without a strongly bilobate projection; elytra in both sexes with black sheen and anterior angles of pronotum acute .............................................................................................. 8

8 Male with an anterior pronotal projection and large temporal process; female pronotum with pair of tubercles near anterior margin ....................................................................................... M. buckleyi (Waterhouse)

8’ Male without anterior pronotal projection, temporal process weak; female pronotum convex and without tubercles ..................................................................................................................... M. tucumanus (Nagel)

9 Male without pronotal projection, male and female with a transverse ridge on both sides of pronotal disc ............................................................................................................................. M. dentifer (Möllenkamp)

9’ Male with anterior, conical pronotal projection; male and female without transverse ridge on both sides of pronotal disc .................................................................................................... M. securiformis (Lüderwaldt)

10 Pronotal longitudinal groove interrupted by a transverse ridge just before the middle (male unknown) ..... ............................................................................................................................... M. amuelleri (Weinreich)

10’ Pronotal longitudinal groove not interrupted, or if so then only near the anterior margin........................ 11

11 Male without bilobed, anterior pronotal projection (sometimes with a triangular lobe)........................... 12

11’ Male with large bilobed, anterior pronotal projection; female pronotum with pair of obscure tubercles and the first three interstriae distinctly smooth ........................................................... M. neotragus (Westwood)

12 Male and female with a triangular, anterior pronotal lobe (in male stronger); female pronotum with punc- tures concentrated along sides and in the longitudinal groove .................................... M. sylviae (Boucher)

12’ Male and female pronota without triangular lobe, female pronotum entirely punctate ............................ 13

13 Head with a round, smooth, impunctate area on vertex; female interstriae dull M. ditomoides (Westwood)

13’ Vertex with surface totally impunctate, female interstriae represented by smooth longitudinal lines .......... ........................................................................................................ M. ranki Grossi & Vaz-de-Mello, n. sp.