Cylindrostethus

Key to males of the species Group 1 (sensu Drake 1952) of Cylindrostethus from Neotropical Region

1. Basolateral processes of proctiger very small, not visible in dorsal view (Fig. 10); small spines present all over the posterior region of sternites V and VI (Fig. 12)...................................................... C. bilobatus Kuitert

1’. Basolateral processes of proctiger long or very long, visible in dorsal view (Figs. 11 and 14); very small spines on central region of sternites IV to VI (Fig. 13)...................................................................... 2

2. Sternites IV and V without depressions; distance between apices of basolateral processes equal or slightly shorter than proctiger (Fig. 03); apices of the basolateral processes of the proctiger, in dorsal view, not hidden by spines of connectives (Figs. 0 1 and 12).............................................................................................. 3

2’. Sternites IV and V with light depressions; distance between apices of basolateral processes greater than 1.2 times median length of proctiger (Figs. 15 and 16); apices of basolateral processes of proctiger, in dorsal view, hidden by spines of connectives (fig. 14)........................................................................................ 4

3. Basolateral processes of proctiger with rounded apices (fig. 11).................................... C. bassleri Drake

3’. Basolateral processes of the proctiger with sharp apices (fig. 0 1, 0 2 and 03)....... C. meloi sp. nov. Floriano and Cavichioli

4. General coloration brown or tan; width of tergite VII not greater than 1.2 times that of tergite II; sternites IV, V and VII with lateral depressions; basolateral processes strongly convergent; anterior width about 3/10 posterior width (Fig. 15)............................................................................................. C. linearis (Erichson)

4’. General coloration blackish; width of tergite VII greater than 1.25 times tergite II; sternites IV, V and VII with central depressions; basolateral processes not strongly convergent; anterior width about 5/10 the posterior width (Fig. 16)....................................................................................... C. erythropus (Herrich–Schaeffer)