Key to species of Pseudoryssomus Gordon

1. Length more than 4.00 mm; postcoxal line incomplete........................................................ 2

1’. Length less than 3.75 mm; postcoxal line complete.......................................................... 3

2. Elytron yellowish red with an oval black spot (Guatemala and Costa Rica)........................ P. formosus Gordon

2’. Elytra yellowish red with a triangular black spot, almost extending to apex, not reaching the humeral callus (French Guiana).................................................................................... P. triangulus sp. nov.

3. Each elytron black with 2 large, reddish-yellow lateral spots narrowly connected along suture (Panama). P. pumilus Gordon

3’. Elytra yellowish red................................................................................... 4

4. Elytra with a large black sutural spot, basally almost reaching the humeral callus, narrowed in the middle, irregularly widening towards the apex, not reaching elytral margin; each elytron with irregularly oval lateral spot on the posterior half (French Guiana).................................................................................. P. brulei sp. nov.

4’. Elytra not as described above............................................................................ 5

5. Each elytron with lateral half red, median half dark brown, outer border of brown area irregular (Venezuela)................................................................................................ P. brevipilosus Gordon

5’. Elytron not as described above........................................................................... 6

6. Elytra with a large and irregular dark brown spot cross-shaped, not reaching the humeral callus (French Guiana)................................................................................................ P. crucifer sp. nov.

6’. Elytra with a large dark brown spot subquadrangular, covering most of elytra, reaching the humeral callus (French Guiana)................................................................................. P. rufomarginatus sp. nov.