Key for the species of Diarthrotarsus, based on Wygodzinsky (1948) and Maldonado (1955)

1. Some connexival segments with conspicuous lateral projections in their basal third............ D. stali Wygodzinsky, 1948

- Connexival segments without lateral projections..............................................................2

2. Fore femur without distinct annuli.............................................. D. travassosi Wygodzinsky, 1948

- Fore femur with distinct annuli, sometimes shortly interrupted.................................................. 3

3. Tubercles behind ocelli conspicuous................................................... D. annulosus (Stål, 1872)

- Without distinct tubercles behind ocelli.................................................................... 4

4. Posterior margin of hind lobe of pronotum without spiniform protuberances between humeral angles (Fig. 13). Apex of abdomen, in dorsal view, truncate, with posterior margin straight (Fig. 17).......................... .. D. guianensis sp. nov.

- Posterior margin of hind lobe of pronotum with a pair of small spiniform protuberances between the humeral angles. Apex of abdomen, in dorsal view, incised at median portion, forming a pair of lobes....................................... 5

5. Dorsal coloration of head, pronotum and scutellum pale brownish; clavus and corium of hemelytra pale with small paler markings, almost whitish. Posterior margin of pronotum almost straight. Apex of abdomen, in dorsal view, more deeply incised at middle, with a pair of large protruding lobes........................................ D. malaisei Wygodzinsky, 1948

- Dorsal coloration of head and pronotum grayish stramineous and stramineous, respectively; scutellum, clavus and corium stramineous, the two latter with reddish tinge. Posterior margin of pronotum slightly concave. Apex of abdomen, in dorsal view, with a small median notch and adjoining lobes not prominent...................... D. marahuacensis Maldonado, 1955