Wheelock says that the vocative singular endings of nouns like filius end in -i but that the vocative singular of adjectives ending in -ius is -ie. Can anyone supply some examples of this type of adjective because I have never seen them. They must be a rare declension of adjective rarely seen.
Ēgregius and socius are two that come to mind. I also checked some Latin grammars and the OLD, and their examples were: augurius, eximius, Lacedaemōnius, patrius, and rēgius.