Mycetomoellerius

1. Median pronotal spines basally fused (Fig. 2, A), rarely separated (Fig. 2, B) [e.g. Mycetomoellerius agudensis (Kempf, 1967), M. holmgreni (Wheeler, 1925), M. isthmicus (Santschi, 1931), M. ixyodus, M. kempfi (Fowler, 1982), and M. relictus (Borgmeier, 1934)].

2. Mandible dorsum smooth (Fig. 2, C), sometimes basally striated (Fig. 2, D), rarely completely striated (Fig. 2, E) [e.g. Mycetomoellerius iheringi (Emery, 1888)].

3. Preocular carinae frequently well-developed (Fig. 2, C), never curved towards the frontal carinae.

4. Pilosity ranging from sparse (Fig. 2, G) to dense (Fig. 2, H).

5. Postocular protuberance generally conspicuous (Fig. 2, F).

6. Vertexal corners varying from rounded (Fig. 2, E) to angled/spiny (Fig. C, D, F).

7. Posterior margin of head generally with strong median impression (Fig. 2, F).

8. Postpetiole in lateral view without posteromedial impression (posterior margin rarely concave) (Fig. 2, H, K).

9. First gastral tergite often with conspicuous pairs of lateral and median ridges (Fig. 2, K).

10. Propodeal projections long in most species (Fig. 2, H).

11. Promesonotum usually with unequally-sized projections (Fig. 2, H) [some exeptions in M. atlanticus, M. farinosus (Emery, 1894), M. fiebrigi (Santschi, 1916), M. holmgreni, M. iheringi, M. oetkeri (Forel, 1908), M. pruinosus (Emery, 1906), M. tucumanus (Forel, 1914), M. turrifex (Wheeler, 1903), and M. zeteki (Weber, 1940)].

12. Antennal scape sometimes with basal lobe (Fig. 2, C) [e.g. Mycetomoellerius cirratus, M. holmgreni, M. iheringi, M. kempfi, M. pruinosus, and M. tucumanus]; microtubercles generally present (Fig. 2, C, D, F).