structure of the mouth-parts in the Body-louse 221 
its base, the distal three-quarters being free. The chitinous parts 
of the Ischnocera and Anoplura are also identical in structure; with 
basal plate, parameres, endomeres, telomeres and penis. Pediculus 
has simpler genitalia, but is not typical of the Anoplura. 
With the female, there are ten ovarian tubules, five on either 
side in Ischnocera and Anoplura, four of these being rudimentary in 
many Amblycera. These exhibit an identical histological structure, 
so much so that Gross (1906, p. 378) states that he could not 
distinguish between them in sections. The oviducts of either 
side unite in a uterus, into which open cement glands for attaching 
the egg to its substratum. In the Ischnocera, and in all Anoplura 
save Pediculus, a receptaculum of remarkable structure opens into 
this uterus by a long narrow duct, the entry of the duct into the 
receptaculum being marked by a conspicuous chitinous ring. 
There is a further correspondence between Ischnocera and 
Anoplura in the secondary sexual characters, and method of 
copulation. In both groups, contrary to what obtains in the 
Amblycera, and in insects in general, the male crawls under the 
female, grasping her hind legs with his front legs, and flexes the 
abdomen upwards to insert the penis. In both groups secondary 
clasping appendages are developed upon the antennae in many 
genera, and these occur always on the third article. 
These comparisons, which have embraced all the systems of 
organs, quite convince me, not only that the Mallophaga and 
Anoplura are very closely related, but also that the Anoplura are 
distinctly more Ischnoceran than Amblyceran im character. In 
this connection it is interesting to note that, while Amblycera 
occur normally upon marsupials, neither Ischnocera nor Anoplura 
are found upon these lower mammals. The general organisation 
that I have outlined also discounts hemipterous affinities for the 
Anoplura, as the Rhynchota differ markedly in every detail of 
structure. 
I consider, then, that the close relationship between Mallo- 
phaga and Anoplura may be taken as definitely established, and 
that in any attempt to explain the mouth-parts of the latter, those 
of the former must be taken into account. The Mallophaga are 
of orthopterous origin, and are most nearly related to the Copeo- 
gnatha, which have fairly typical orthopterous mouth-parts. These 
parts have undergone successive reduction in the two Mallophagan 
sub-orders. The Amblycera have mandibles, a maxilla consisting 
of a basal piece formed of fused cardo and stipes, with a four- 
jointed palp, and an undivided endopodite. (A chitinous splint 
homologous with the Psocid “fork” occurs in most Amblycera. It 
this belong to the maxilla, a thing of which I am personally not 
convinced, then what I have called an undivided endopodite would 
consist of galea only.) The labium is reduced, and consists of 
