- sclerites present on pro-, meso-, and metanota;
- mesonotum completely covered by 2 sclerites, separated by unbranched longitudinal suture;
- metanotum incompletely sclerotized with 3 pairs of small sclerites in anteromedian, posteromedian and lateral
positions [only 5 sclerites in Hydatophylax spp., metanotal sclerites reduced to just setal groups in some
species];
- prosternal horn present [absent from Drusus chrysotus Rambur 1842];
- antennae situated halfway between eyes and anterior head margin;
- fleshy protuberances present laterally and dorsally on abdominal segment I.