98 
Mallophaga 
As to the position of the Ralli, they possess as their most widely 
distributed and characteristic parasites two well-marked genera, 
Rallicola and Pseudom.enopon, one in each of the sub-orders of Mallo¬ 
phaga. Rallicola would seem to be a somewhat primitive genus, 
certainly more primitive than Philopterus and Degeeriella, the remaining 
genera of the same family; while the relation of Pseudomenopon to the 
other menoponid genera cannot, in the absence of any form showing 
an intermediate condition, be stated. The fact that Pseudomenopon 
does not occur on either Parridae or Apterygidae may indicate that it 
is of more recent development than Rallicola. An important negative 
fact is the non-occurrence of Philopterus upon rails. This genus, which 
is generally looked upon as the most specialised of the more specialised 
sub-order, is almost universally distributed among birds. The only 
important groups that are without it are the Galliform complex, 
comprising tinamous, fowls, pigeons, the hoatzin, and, on Mallophagan 
evidence, the penguins; and the Ratitae. Three or four species of 
Philopterus have certainly been described from some of the larger rails, 
but I have carefully searched a large number of species of ralline birds 
from all parts of the world without finding Philopterus ; while all 
yielded Rallicola, and many Pseudomenopon. It is fairly obvious, 
then, that Philopterus can only have been acquired at a comparatively 
recent date by those species which possess it. Species of Degeeriella, 
Lipeurus, and Laemohothriwm are also too f&w in number and too 
circumscribed in distribution to be included in other than the same 
category. The intrinsic parasites of the Ralli stand, then, in an isolated 
position with regard to the remaining Mallophaga. And all the evidence 
of Mallophagan distribution points to the conclusion that the condition 
of the parasites is intimately connected with the phylogenetic relation¬ 
ships of the hosts, and reflects these relationships to a greater or less 
extent. Consequently I cannot avoid the conclusion that the Ralli 
occupy an isolated position, which should entitle them to at least the 
same rank as the similarly isolated Galliform complex. 
It may be as well, at this point, to clearly define my position in 
making such statements as to bird relationships as that conveyed in 
my last sentence. These statements are made frankly upon the 
evidence afforded by the parasites. They are, consequently, not com¬ 
parable with the statements of a morphologist, based upon structural 
considerations; but are to be looked upon simply as suggestions, which 
I believe may be well founded, but which, until they receive morpho¬ 
logical confirmation, must remain simply suggestions. I may state 
