Key to the species of the genus Hamma
1 Posterior pronotal process without terminal spine............................................................ 2
- Posterior pronotal process with a terminal spine............................................................. 3
2 Pronotum with reddish brown blunt tubercles................................................... franciscae n. sp.
- Pronotum with black thorn-like tubercles.......................................................... carlini n. sp.
3 Suprahumeral horns prominent, ending in a thorn............................................................ 4
- Suprahumeral horns absent or not prominent, apex blunt...................................................... 14
4 Posterior pronotal process quite slender in lateral view without well evident nodes.................................. 5
- Posterior pronotal process in lateral view with well evident nodes............................................... 6
5 Suprahumeral horns globose (better visible in frontal view)............................................ cinnameus
- Suprahumeral horns conical....................................................................... capeneri
6 Suprahumeral horns very large, posterior process heart-shaped in dorsal view............................... fabulosum
- Suprahumeral horns smaller, posterior process not heart-shaped in dorsal view..................................... 7
7 Pronotum with reddish tubercles.................................................................... nodosum
- Pronotum with black tubercles........................................................................... 8
8 Suprahumeral horns upturned.................................................................... brevicornis
- Suprahumeral horns laterad.............................................................................. 9
9 Posterior process with terminal node large and clearly rounded in dorsal view..................................... 10
- Posterior process with terminal node quite slender, not rounded in dorsal view.............................. robustum
10 Suprahumeral horns about half as long as pronotal width (dorsal view).......................................... 11
- Suprahumeral horns about 1/4 to 1/3 as long as pronotal width (dorsal view)...................................... 13
11 Posterior process V-shaped in lateral view between second and third node........................................ 12
- Posterior process straight in lateral view between second and third node..................................... rectum
12 Suprahumeral horns straight in dorsal view........................................................... grahami
- Suprahumeral horns curved backwards in dorsal view..................................................... heimi
13 Posterior process shorter than tegmina, suprahumeral horns with short, stout terminal spine............... boulardi n. sp.
- Posterior process as long as the tegmina, suprahumeral horns with slender terminal spine...................... spinosum
14 Posterior process in dorsal view with large terminal node............................................... ugandensis
- Posterior process in dorsal view with very small terminal node................................................. 15
15 Posterior process slender in lateral view................................................................... 16
- Posterior process quite strong in lateral view......................................................... pattersoni
16 Flanks of the pronotal helmet and thoracic pleurae covered by white pilosity; posterior process with lateral carinae... simplex
- No presence of white pilosity; posterior process without lateral carinae................................... pygmaeum