ABSTRACT
Pronotum distinctive, covering head when at rest; shieldlike and variously semicircular, sub-pentagonal, sub-triangular, sub-trapezoidal, etc., with explanate margins and raised disk, occasionally with a midline groove, rarely a carinula; surface smooth, punctate, or granulate, median and lateral vittae often present and diagnostic (i.e. vittagrams); hypomera, large and not reaching anterior margin (i.e. “open”) in most American species (see Key). Bright colors (apparently pterodine pigments) are often present in the pronotal and neck region, and are potentially of some taxonomic use. Prosternum short, prominent, procoxal cavities open, procoxae conical, prominent, and contiguous; mesosternum short, mesocoxae prominent, conical, contiguous; metasternum longer, broad, mesal margins of metepisterna straight or nearly so, not curved or sigmoid; metacoxal cavities open, metacoxae transverse and contiguous. Trochanters quadrate, interstitial, angularly joined to their femora. Femora flattened, somewhat swollen. Tibia stout, somewhat flattened, apical spurs present or absent; tarsal formula 5-5-5, slender, penultimate tarsomere with pads (pulvilli); claws simple or variously forked (bifid), occasionally with a basal protuberance. Scutellum evident and triangular. Elytra with explanate margins, sometimes with longitudinal ridges (costae), and sides variously nearly parallel, somewhat or considerably widest in middle, or tapering and narrowing in posterior third or so. Elytral bead and margin often pale in color, contrasting with disk. Elytral vestiture sometimes provides useful characters for species identification, e.g., Pyractomena.
