ANTRICOLA is descr. and separated from Ornitho-doros; its genotype is 0. eoprophilus McIntosh. Amblyomma gertschi is from the 3-toed sloth, Canal Zone. A study of the type of I. diversifossus, a sp. from New Mexico, reveals that it is distinct from the western and northern tick heretofore considered as belonging to this species. This latter tick has been found to be identical with "Ixodes dentatus var. spinipalpis Hadwen and Nuttall 1915." I. spinipalpis is given specific rank.