Key to species of Diponthus

1. Macropterous insects. Pronotum with a median longitudinal light-colored band….................................. 2

- Brachypterous insects (Figs. 3k, l, and 5a–d). Pronotum without a median longitudinal light-colored band (Figs. 3l, and 5d)................................................................................... D. colorbellus sp. nov.

2. Prosternal tubercle with apex directed backwards. Interocular distance wide (wider than the width of fastigium apex)..... 3

- Prosternal tubercle with apex straight. Interocular distance wide or narrow........................................ 6

3. Pronotal disk with a longitudinal band and two lighter-colored oblique bands in prozona............................ 4

- Pronotal disk with three light-colored longitudinal bands..................................................... 5

4. Oblique bands not reaching the metazona (Fig. 7b); body color dark-brown, black and yellow-ocher, completely black-mottled (Fig. 3c, d); tegmina with background black and incomplete transverse veins yellow (Figs. 3c, d, and 8e); male furculae small (Fig. 9b)................................................................................... D. cribratus

- Oblique bands reaching the metazona (Fig. 7b); body color shiny black and yellow-ocher, not mottled (Fig. 3e, f); tegmina with background green and complete transverse veins delimiting irregular cells (Figs. 3e, f, and 8f); male furculae larger (Fig. 9b)............................................................................................ D. festivus

5. Frons straight in lateral view (Figs. 3g, and 7a); male cerci very long, digitiform (Fig. 9a); larger body size (males: x̄ 35, 3 mm; females: x̄ 46 mm) (Fig. 3g); fore and middle femora robust (Fig. 3g); tegmina green (Fig. 3g, h)................ D. dispar

- Frons rounded in lateral view (Figs. 3i, and 7a); male cerci shorter, tapering towards the apex (Fig. 9a); smaller body size (males: x̄ 26, 8 mm; females: x̄ 38, 3 mm) (Fig. 3i); fore and middle femora thinner (Fig. 3i); tegmina with discal area greenish, medial area hyaline, anal area green (Figs. 3i, j, and 8h)................................................ D. electus

6. Interocular distance wide (Fig. 7b); large insects (males: x̄ 45, 3 mm; females: x̄ 57, 1 mm) (Fig. 3a); median dorsal carina of pronotum cut by the main transverse sulcus (Fig. 7b); body completely mottled (Fig. 3a, b)............. D. nigroconspersus

- Interocular distance narrower; medium size insects (males from 19 to 33 mm; females from 25 to 47 mm); median dorsal carina of pronotum cut by more than one transverse sulcus; body mottled or not mottled.................................. 7

7. Pronotal disk with three light-colored longitudinal bands (Fig. 7b); body color yellow, black and orange-reddish (Fig. 2e, f)........................................................................................... D. puelchus

- Pronotal disk with one longitudinal band and continuous or discontinuous oblique bands; body color not as the pattern described above............................................................................................... 8

8. Transverse sulci of pronotum slightly deep; epiphallus with lophi perpendicular to the bridge......................... 9

- Transverse sulci of pronotum deep; epiphallus with lophi parallel to the bridge.................................... 13

9. Male cerci short, not surpassing the end of epiproct, conical (Fig. 9)............................. D. dilatatus sp. nov.

- Male cerci longer, surpassing the end of epiproct, gradually tapering towards the apex.............................. 10

10. Caudal margin of pronotal disk obtuse-angular; male cerci with acute apex; valves of cingulum narrow at base, with subcircular (Fig. 10a) or oblong distal portion (Fig. 10b).............................................................. 11

- Caudal margin of pronotal disk nearly straight; male cerci with straight or blunt apex; valves of cingulum subtriangular (Fig. 10i, j)............................................................................................. 12

11. Body always mottled, general color red or yellow and grey (Figs. 2c, d, and 6e, f)...................... D. pycnostictus

- Body not always mottled; color variable (Figs. 2a, b, and 6a–c)...................................... D. argentinus

12. Body color dark green and yellow, not mottled (Fig. 2g, h); tegmina with transverse veins delimiting cells (Figs. 8k)............................................................................................. D. paraguayensis

- Body color red, black mottled (Figs. 2i, j, and 5e, f); tegmina with longitudinal veins well-marked, yellow (Figs. 8l)......................................................................................... D. paranaensis sp. nov.

13. Disk of pronotum with a median longitudinal light-colored band (Fig. 7b); tegmina reddish (Figs. 4g, h, and 8p); male cerci long, with wide and blunt apex (Fig. 9a)......................................................... D. porphyreus

- Disk of pronotum with a median longitudinal light-colored band and with spots obliquely arranged in the prozona; tegmina of a different color; male cerci shorter, with thinner apex....................................................... 14

14. Tegmina with subcostal and radial veins cream-colored and posterior cubital strong yellow (Fig. 4e, f)......... D. virgatus

- Tegmina with all longitudinal veins of the same color........................................................ 15

15. Body color black and yellow-ocher (Figs. 4a, b, and 6i); tegmina with well-delimited cells, without spots or mottles on the transverse veins (Figs. 4a, b, and 8m); male cerci short and conical (Fig. 9a); valves of cingulum with distal portion expanded, anterior margin straight, upper margin slightly notched (Fig. 10m)........................................ D. crassus

- Body color dark brown (Figs. 4c, d, and 5h); tegmina with irregular transverse veins, not delimiting cells, and with spots on transverse veins (Figs. 4c, d, and 8n); male cerci longer (Fig. 9a, b); valves of cingulum of a C shape (Fig. 10n).............................................................................................. D. salvadorii sp. nov.