53 
It has not been recorded from this country, but may be looked for 
upon our species of swans, as the lice infesting these birds are generally 
widely distributed. 
LOUSE OF THE GUINEA PIG. 
(Gyropus gracilis Xitzsch.) 
The Guinea pig is perhaps a rather unimportant fac 
tor among the domesticated animals, but it supports it* 
due quota of parasites, nevertheless, and they require a 
brief mention at least. They are quite interest! 
structure, differing largely from any of the species con 
sidered hitherto. 
The one to first receive notice, and probably the one 
here given, was referred to by Schrank under the name 
of Pediculus porcelli, but Xitzsch, in 1818, described it 
as Gyropus gracilis, a name which has been used by all 
subsequent writers. 
It is referred to generally by writers on the subject 
and would seem to be a fairly common species where 
guinea pigs are kept. It has not been met with in this 
country so far as records show, but may be looked for 
with great probability of success in any place where 
guinea pigs are kept in numbers. 
Denny characterizes it as "elongate, pale, fulvous- 
yellow, finely pubescent ; head and thorax darker, seg- 
ments of the abdomen with transverse striated fascia at 
the sutures; tarsi and ungues very short and minute." 
Fig. 40.— Gyropus 
gracilis. (A-fter 
Denny ) 
F1G.--41. 
Gyropus ovalis. 
Denny ) 
(Aitt 
(Gyropus oralis Xitzsch.) 
This is a form closely related to the preced- 
ing species, and observed and described by 
Tsitzsch at the same time. It differs from that 
species in the much snorter and broader body, 
and is, according to Denny, kk pale yellow- 
white ; head and thorax bright ferruginous, 
the former transverse : temporal lobes pro- 
duced ; abdomen large, nearly orbicular; legs 
thick, the two posterior pairs curved ; ungues 
long, curved, and strong." 
The scanty hair of the guinea pig makes the 
application of washes for the destruction of the 
lice a very simple matter, BO that wherever it 
is a matter ot importance there need be no 
difficulty in ridding the animals of the para- 
sites. 
