These characters were: shape of posterior margin of pronotum (produced or extended medially vs. oval or broadly); width of subgenal suture and ventral distance between antennal scrobes (narrow vs. wide); relationship between interocular space and width of rostrum at base (one-third or less vs. not less than one-third); shape of dorsal tip of rostrum (grooved or nearly truncate vs. oval distally).
Source: wiktionary