Tue Hoa Lovuse 645 
Several attempts have been made to feed the lice on guinea pigs, but 
without success. The dense hair of the pigs hampers the movements 
of the lice, and, if shaving be resorted to, the lice are left without a foot- 
hold. If the finger be pricked and lice brought in contact with the freshly 
escaped blood, the lice immediately move away. Widmann (1915 b: 
1337) described a similar reaction in man-infesting lice, which refused to 
feed on various organs just removed from freshly killed mice. 
When placed on the arm, hog lice may feed at once or may move about 
more or less rapidly. When walking they appear to move sideways as 
often as straight forward with the head in front. The peculiar structure 
of the feet, first described by Osborn (1891:20 and 1904:107), enables 
the lice to grasp the hairs on the arm. The tibia (Plate LVIII, 1) increases 
at the distal end to twice the width of the proximal end, and the dorsal 
half only articulates with the tarsus. The remaining part is concave and 
its ventral border is drawn out to a spur, bearing a stout spine at the apex. 
In the concavity rests a stalked, protrusible, subcircular pad bearing two 
spines and two hairs. On the inner edge of the tarsus, in line with the. 
surface of the extended pad, is a blunt precess bearing a spine. The 
inner surface of the claw is slightly serrated. In holding a bristle or a 
hair, the claw is bent over to rest on the tibial spur and the pad is pushed 
against the opposite side of the bristle, thus preventing the insect from 
slipping. Enderlein (1904:141), to whom Osborn’s earlier description 
as evidently unknown, describes the pad as a strongly chitinized skeletal 
iece of triangular shape. In specimens cleared in potash and mounted 
der a cover glass it frequently has this shape, while in living and in 
ncleared specimens it always appears subcircular. Enderlein names 
his pad the pretarsal sclerite, which name is retained by Neumann (1911: 
07) in his description of the insect. 
The earliest description of a louse feeding is that of Hooke (1665:211- 
13). He described the passage of blood from his arm into a louse which 
e had placed there after it had fasted for several days, and the working 
f a pumplike apparatus in the head. Swammerdam (1682, English 
rans. 1758:33-35) gave a more detailed description, but he disagreed with 
ooke’s description of the mouth parts, saying: ‘‘ The louse has neither 
eak, teeth, nor any kind of mouth, as Dr. Hooke described it, for the 
ntrance into the gullet is absolutely closed; in the place of all these, it 
as a proboscis or trunk, or, as it may be otherwise called, a pointed and 
