Marsicus
Could not find Marsica in Logeion dictionaries.
Marsica proper-name adjective neuter nominative plural, proper-name adjective neuter vocative plural, proper-name adjective feminine nominative singular, proper-name adjective feminine ablative singular, proper-name adjective feminine vocative singular, proper-name adjective neuter accusative plural of Marsicus
Mārsĭcus, (14) a, um, des Marses : Cic. Div. 1, 99 ; Agr. 2, 90 ; Mart. 13, 121, 1.