Fifteen strains of group C arboviruses belonging to five distinct antigenic types were isolated from rodents in Almirante, Panama during 1961 and 1962. Caraparú and Madrid viruses were recovered from sentinel mice. One isolation of Nepuyo virus was made from a spiny rat. Two new members of the group, Patois and Zegla, were obtained from sentinel mice and cotton rats. Descriptions of these new types are included.