A. D. Peacock 
115 
runs along the side of the posterior part of the sac, along and above the ramus 
of the ventral element of the ventral stabber, to its insertion under the distal 
end of the dorsal element. 
The Salivary Glands are situated laterally at about the middle of the 
thorax and consist of two pairs of glands, one pair bifurcated and tubular 
and the other reniform. 
The bifurcated tubular glands lie above the anterior stomach pockets and 
are deeply embedded in fat-cells which closely invest the oesophagus and the 
anterior of the stomach and its pockets. They are about 0*1 mm. in length, 
and possess a long duct which runs forward to the stabber sac. 
The reniform glands are shorter, lie nearer the median line inner and 
slightly posterior to the tubular glands between the stomach pockets and the 
oesophagus. From the hilum of each gland there arises a duct which runs 
forward and parallel with the duct of the bifurcated gland. 
The terminations of the salivary ducts in the region of the posterior end 
of the stabber-sac are of interest. Martin (1913, p. 46) figures the four ducts 
entering the stabber-sac posteriorly, the figure having been drawn from a 
dissection made by Bacot. Lloyd’s preparation also demonstrates this but 
shows, to my judgment, that the ducts enter the posterior dilatation of the 
salivary pipe. 
MANNER OF FEEDING. 
When the louse desires to feed, certain parts of the mouth apparatus 
have to be brought externally into action from their concealed positions in 
the head, and what probably happens is as follows. The contraction of the 
buccal and pumping-pharyngeal protractors causes the food canal and stabber- 
sac to be brought forward. The sac must be affected because its chitin is 
continuous with that of the buccal region: (1) the buccal funnel and the 
attached pumping-pharynx are brought forward; (2) the dental region 
becomes everted so that the hood-like haustellum and the teeth are placed 
externally; (3) the post-dental region comes to touch the skin of the host; 
(4) the elements of the pumping-pharyngeal tube, by reason of their union 
with the pumping-pharynx, are brought forward and touch the skin also; 
(5) the elements of the sac tube are also brought far forward to this point. 
The contraction of the sac protractors brings the stabbers into play and also 
influences the sac. Though I have no preparations proving it what probably 
happens to the sac is that (1) the posterior part of the thin roof becomes 
telescoped; (2) the sac floor groove reaches a forward position so that the 
anterior extremity lies beneath the posterior extremities of the elements of the 
sac tube; (3) the lateral floor grooves are moved forward also to lie beneath 
these elements; (4) the thin sac floor anterior to the grooves also becomes 
telescoped. 
Because of the structure of the tips of the stabbers they produce a 
lacerated wound. Whether there is any boring motion or a repetition of 
stabbing by the prickers in the wound I cannot say. From their small size 
8—2 
