Having recently put my own collection of Dectcidæ into systematic order and treated the collection of the U. S. National Museum entrusted to me by Dr. C. V. Riley in a similar manner, I have thought it would assist n obtaining better material for a future monogroph if I were to publish at least a generic discriminatio of the material at hand. At the same time I am able to clear up most of the synonymy of the species and assign to therir proper location the various described species, very few of which (7 out of 23) will be found to hae been originally placed in the genera to which they are here assigned.