320 DR. A. E. SHIPLEY ON [Mar. 16, 
Epizoa.’ Piaget, in his ‘ Les Pédiculines,’ states his conviction, 
that WV. cameratus is specifically identical with the V. quadrulatus 
of Nitzsch, from Tetrao wrogallus, the Capercaillie. Kellogg in his 
Mallophaga (‘ Genera Insectorum ’) does not mention WV. cameratus 
though he records V. quadrulatus from 7. urogallus, T. tetrix, 
and Lophophorus impeyanus. 
NVirmus is a more slender animal than Goniodes, and appears 
to be longer. It is rarer than the latter, though in the great 
majority of cases the two are found together. Most of what has 
been said above about Gloniodes applies also to Virmus, as their 
habits are very similar, except that Virmus lives more on the 
skin and upon the base of the rachis of the feather than does 
Goniodes. It also seems to frequent the feathers under the wing, 
where Goniodes is seldom seen. Both species seem to wander all 
over the body ; and though they seem rather more common upon 
the head, neck, and back, the old view that these biting-lice 
oceur chiefly or exclusively on those parts of the body inaccessible 
to the beak was not borne out by our investigations (Pl. XLI. 
figs. 17 & 18). 
The variation in size and in colour is very considerable. Dead 
specimens are not infrequently found, and these may be in some 
cases mistaken for cast skins. An average length is 3 mm., and 
an average width of the abdomen is 15mm. The abdomen is 
the widest part. In no case did we find either Goniodes or 
WVirmus in the crop of the grouse, though, as we have just stated, 
they are fully exposed to being snapped up by the bird’s beak if 
the bird cared to notice them. It is not known exactly how 
clean birds get infected: probably the Mallophaga simply crawl 
from one bird to another when the latter are contiguous, and the 
young birds are infected on the nest. There is evidence, however, 
that in some cases, probably rare ones, they cling to the grouse- 
fly and are by it transported to a new host. 
In the summer of 1907 Mr. Fryer found some Mallophaga 
eggs. These were for the most part empty, but from one or two 
full ones he has succeeded in hatching out specimens of Virmus 
cameratus. ‘The eggs are white, and transparent when empty, 
just visible to the naked eye, 0-6 mm. in length, and about four 
times as long as they are broad. Each egg-case is beautifully 
reticulated, the areas between the reticulations being six-sided. 
At one end the egg has a cap which is pushed off when the young 
emerges. The eggs are laid between the barbules of the vanes or 
near the bases of the filo-plumes, and adhere to their supports by 
means of some sticky excretion (Pl. XLII. fig. 20). 
The eggs appear to be laid throughout the summer; the first 
time we found them (some of them were empty) was on 2nd July, 
1907, and we found others later in the season. 
There is no metamorphosis ; the young emerge from the egg- 
case as small miniatures of their parents. They seem to cast 
their skin several times, but the exact number of ecdyses is not 
known. 
