Abstract:
Werneck (Mem. do lnstit. Oswaldo Cruz, XXXI, iii, pp. 496-589, 1936) recently reduced the family Trichodectidae to a single genus, but such a procedure is unwarrantable. If one examines casually the figures of species in books it is usually possible to say from what kinds of animals the specimens had been obtained. For instance, one cannot mistake species taken from cats and mongooses, they all show a family likeness, likewise species found on various other groups of animals, and for this reason I consider they should be placed in separate genera. Some time ago I received from Mr. G. B. Thompson three new species of Trichodectidae taken off Procavia emini in the Belgian Congo. Two of these species were typical parasites of procaviidae, but the specimens (a female and a male) of the third species were undoubtedly stragglers; a mere glance at these was sufficient to convenience that they were not parasites of Procavia, but a new species of Trichodectes parasitic on a species of Canidae, or animal closely related to the Canidae. If one segregates the species of Trichoclectidae into different genera, and finds that by doing so the species tell one something about their hosts, then I feel that one is justified in splitting up the family. The same applies not only to the species of Mallophaga parasitic on mammals, but also to those parasitic on birds. The generic characters may not always be very striking, but no one could confuse, let us say, species of Actronith ophilus, which are parasitic on Charadriiformes, with species of Heleonomus, parasites of cranes. It is impossible to lay down any hard and fast rules as to what should be considered generic characters, because what may be a generic character in one family may not be a generic character in another.
