48 PROCEEDINGS OF THE NATIONAL MUSEUM VOL. 120 
Aviparasitological Relationships 
Since Mallophaga are obligatory, usually highly host-specific, 
external parasites, their distribution is dependent on the distribution 
of their hosts (Emerson and Ward, 1958). The arrangement of the 
Mallophaga based on morphological similarities does not follow 
exactly Peters’ (1945) phylogenetic arrangement of the hornbill 
hosts (table 13). In the genus Chapinia, species of the lophocerus 
species-group infest hosts in the genera Tockus, Bycanistes, and 
Ceratogymna of the Ethiopian region, but species of the acutovulvata 
and hirta species-groups infest hosts in the genera Tockus, Anorrhinus, 
Penelopides, Rhyticeros, Anthracoceros, and Buceros of the Oriental 
and Australasian regions. Species of Bucerocolpocephalum infest 
hosts in the genera Ptilolaemus and Anorrhinus of the Oriental region. 
In the genus Bucerophagus, the species B. forcipatus of the forcipatus 
species-group infests hosts in the genera Buceros and Rhinoplax of 
the Oriental region, but species of the productus species-group infest 
hosts in the genus Bucorvus of the Ethiopian region. 
Tockus is the only hornbill genus with amblyceran lice that has 
members in both the Ethiopian and Oriental regions (table 13). 
Yet the amblyceran, Chapinia clayae, from the Oriental species, 
Tockus birostris and Tockus g. griseus, does not resemble members of 
the lophocerus species-group which infest other species of Tockus. 
Instead, C. clayae resembles most closely C. acutovulvata from the 
Oriental species of Anthracoceros. It would appear that there has 
been more recent contact between the Indian Tockus and Anthraco- 
ceros whose ranges overlap than between the more nearly related 
Indian Tockus and African Tockus. Kellogg (1896) was the first to 
mention that Mallophaga live their entire lives on the host bird and 
that infestation of new hosts is accomplished by the actual migration 
of individuals from one bird to another, during copulation, nesting, 
or roosting. Clay (1949b) stated that normally birds of different 
species did not come into close enough contact for lice to be trans- 
ferred from host to host but that interchange of lice could take place 
between predator and prey, nestling and foster parent in brood 
parasites, by the use of common dust baths (according to Hoyle, — 
1938), and by phoresy, which is the transfer of lice by Hippoboscid 
flies. In the case of brood parasites she stated that for the European 
Cuckoo, Cuculus canorus, lice of the foster parents had never been 
established on the cuckoo. She further stated that establishment 
on the new host might be prevented by competition of the already 
adapted resident louse population, by the host specificity of the 
immigrant louse making feeding and development on the new host 
impossible, or by the fact that only males or unfertilized females had 
been introduced. Clay (1962) described natural straggling as 
