Optatus Pascoe

Key to the known species of Optatus and Macroptatus

1 Procoxae nearly contiguous (Figs. 8–9); prosternal canal at least frontally with lateral ridges; elytron without transverse color pattern; interstria 9 carinate throughout; body length <10 mm; Optatus.......................................... 2

- Prosternal process separating procoxae by about 1/4 their own width (Figs. 10–11); prosternal canal without lateral ridges; elytron with transverse pattern (fascia or spots); interstria 9 carinate in basal half; body length> 10 mm; Macroptatus..... 5

2 Pronotum with interstices forming fine vermiculate ridges; prosternal canal anteriorly as wide as procoxa; mesosternal interspace of metaventrite not protruding beyond mesocoxa; male rostrum without dorsomedian carina; vestiture generally evenly distributed.......................................................................................... 3

- Pronotum with interstices wide and irregular; prosternal canal not nearly as wide as procoxa; mesosternal interspace of metaventrite often protruding slightly beyond apex of mesocoxa; male rostrum with dorsomedian carina; vestiture unevenly distributed, either arranged in fascicles or with glabrous portions.................................................... 4

3 Pronotum and ventrites with vermilion vestiture; body slightly stouter, with elytral apices more narrowly rounded; México south of Transmexican Volcanic Belt to Guatemala................................................. O. palmaris

- Pronotum and ventrites with vermilion vestiture reduced or absent; body slightly more elongate, with elytral apices more broadly rounded; Guatemala [plus 1 unconfirmed record from Costa Rica in MfNB]...................... O. inornatus

4 Body stout, elytra across humeri almost as wide as long; dorsal vestiture sparse except on distal third; interstria 9 distinctly carinate; Panamá........................................................................... O. stockwelli

- Body more elongate, elytra distinctly longer than wide; dorsal vestiture fasciate but evenly distributed; interstriae 7–10 partially carinate or at least convex; central México to Costa Rica.......................................... O. fasciculosus

5 Vestiture black with vermilion elytral fascia, metaventrite anteriorly protruding well below mesocoxa; rostrum with ventrolateral margin coarsely corrugated; pronotum with notosternal suture obliterated in anterior 2/3; Costa Rica.... M. championi

- Vestiture khaki with transversely arranged dark spots; metaventrite anteriorly not protruding below mesocoxa; rostrum with ventrolateral margin moderately corrugated; pronotum with notosternal suture obliterated in anterior 1/2; México east of Isthmus of Tehuantepec, El Salvador............................................................... M. deppens