Some time ago Dr. Uhler was kind enough to lend me the types of C.pluto for study in connection rvirh some aliied material from the National Museum. This new material, while generically distinct, is so closely allied to Cochlorhinus in many ways, and at the same time possessing more nearly the typical Acocephaline characters, that it is now possible to assign this unique genus to an approximately correct position in the group,and give its characters from a comparative standpoint.

It is apparentiy a rare form, as the three original females taken more than twenty-five years ago are the only known specimens of the species. To make this nondescript form more accessible to the workers in the group, and as a basis for the comparisons in tlie descriptions that follow,it has been thought best to give a comparative description of the genus and species, and also a figure of the type, together with its more important details.