Key to species of Pseudastenus Bernhauer

1. Elytra shorter than pronotum, 0.9 times as long as pronotum, sides divergent to posterior margin, widest at posterior margin. ................................................................................................... 2

- Elytra longer than pronotum, ranging between 1.1 and 1.4 times as long as pronotum, sides slightly curved, widest in front of posterior margin...................................................................................... 4

2. Eyes reduced, approximately only 0.20 times as long as total length of head; postocular length more the two times longer than eyes; elytra unicolored or not conspicuously bicolored........................................................ 3

- Eyes less reduced, approximately 0.30 times as long as total length of head; postocular length only 1.6 times as long as eyes; elytra conspicuously bicolored, with distinct black anterior half......................................... P. barretoi

3. Eyes slightly larger; postocular sides approximately parallel; elytra slightly bicolored, anterior half of elytra indistinctly darker than posterior half.......................................................................... P. ribeirocostae

- Eyes slightly smaller; postocular sides divergent; elytra unicolored yellow................................ P. schubarti

4. Eyes large, 0.33 times as long as total length of head; postocular length equal to eye length................... P. oculatus - Eyes smaller, between 0.24 and 0.31 times as long as total length of head; postocular length distinctly longer than eye length ................................................................................................... 5

5. Pronotum light brown; elytra with basal half darker than apical half (in some specimens not so conspicuous)............. 6

- Pronotum rust brown to reddish; elytra with basal two-thirds darker than apical onethird................... P. ferrugineus

6. Larger, at least 3.00 mm long; elytra bicolored, dark brown to black in anterior half and light brown in posterior half; aedeagus with apical sclerites of internal sac not elongate............................................................. 7

- Smaller, 2.20 mm long; elytra unicolored light brown; aedeagus with apical sclerites of internal sac elongate and straight............................................................................................ P. amazonicus

7. Head light brown; median lobe of aedeagus with apical sclerites entirely narrow and S-shaped (Figs. 46–47).... P. plaumanni

- Head dark brown; median lobe of aedeagus with apical sclerites broad on the basal half and not S-shaped (Fig. 50)... P. latus