4 THOMPSON YATES AND JOHNSTON LABORATORIES REPORT 
of all the segments highly chitinised. Legs resembling those of the male ; 
but the tarsi of Leg f. and ii. (fig. 7) are attenuated anteriorly. Anal seg- 
ment (fig. 8) with two broad, thin plates, each bearing three minute hairs. 
Average length of both sexes, 1.4mm. ; width, 5mm. 
The larva closely resemble the adults ; but the abdomen is much smaller 
and the hairs projecting from it are proportionately very long ; the segments 
carry a fringe of only four hairs instead of many as in the adults. 
Ovum, with a comparatively large clasping organ or pedicel ; anterior 
pole with an irregular emarginate cap, which splits off at the period of hatch- 
ing. The eggs are attached to the hair of the host at about one-third of the 
distance from the base, and measure approximately, .5 by .2mm. 
INTERNAL ANATOMY. 
Alimentary Canal. — This organ consists of the following portions :— 
Fore-gut. 
Mouth. 
Chitinous pharyngeal pump. 
Oesophagus. 
Mid-gut. 
1st portion or descending part of mid-gut. 
2nd portion or ascending part of mid-gut. 
Pyloric ampulla with the origin of malpighian tubules. 
Hind-gut. 
Intestine. 
Rectum. 
The mouth is very small. The opening is situated beneath the prow-like 
anterior portion of the head. 
The -pharyngeal pump is long and narrow. It passes through the head 
and into the thorax. It ends in the front part of the thorax in a number of 
chitinous bars. 
The oesophagus passes backwards and upwards, surrounded by the large 
ganglionic masses. It is a delicate wrinkled tube, much folded upon itself. 
It enters the large and massive mid-gut with no appreciable proventricular 
fold. 
The mid-gut is sharply bent upon itself, so that it forms a U-shaped 
organ. The first portion is the largest and its walls are thickest. It is 
lined by large granular cells with large nuclei. In the distended organ the 
cells are flattened. In the empty viscus they are cubical. Externally there 
are longitudinal and circular fibres arranged to form an open network. 
During life rythmical contractions are constantly taking place. The contents 
are blood, either unaltered in appearance, or partially digested. The mid- 
gut, especially the more massive first portion, occupies, when distended, most 
of the abdominal space not taken up by the ovaries. 
The pyloric ampulla is a dilated portion of the mid-gut supplied with 
numerous circular muscles. Four malpighian tubules open into it. These 
