688 LAURA FLORENCE 
epithelium, and appears to be continuous with the posterior end of the 
chitinous bulb which marks the termination of the salivary duct. 
The two pairs of thoracic salivary glands lie closely apposed to either 
side of the anterior end of the stomach, and the long, horseshoe-shaped 
gland is folded around the oblong-ovate gland in a characteristic manner 
(Plate LXII, 3). In the man-infesting pediculi the glands are described 
as ‘kidney-shaped ’”’ and “ horseshoe-shaped,’”’ and their position in the 
thorax has been variously figured by a number of authors but the smaller 
one has never been shown surrounded by the larger. Strdbelt (1882, 
English trans. 1883:89) described the glands of Linognathus vituli (Haemato- 
pinus tenuirostris) as “ elongated’? and “ globular,” and thought that 
the efferent duct of the former was situated at one end of the gland and 
that the horseshoe appearance was due entirely to the position of the 
gland at rest. The length of the horseshoe-shaped gland (Plate LXII, 4) 
is approximately 0.66 millimeter and the width of the arms 0.33 milli- 
meter. The length of the oblong-ovate gland (Plate LXII, 5) is 0.12 mil- 
limeter and its width 0.05 millimeter. The large cells of the epithelial 
lining shine through the outer membrane of the gland, and at the exit 
of the duct the transition from these to the small cells lining the duct can 
be seen even in gross specimens (Plate LXII, 6). In sections the epithelial 
cells are seen to be considerably larger than those of Pawlowsky’s glands, 
and the nucleus, with its dark-staining nucleolus, lies rather toward the 
base of the cell. There is a distinct though small lumen within each 
gland. The efferent ducts of the two glands pass cephaiad without 
uniting. In gross dissection they have been followed as far as their 
entrance to the head, but their union with the salivary duct lying between 
the dorsal and ventral elements of the piercers has not been seen. In 
his description of dissections prepared by Mr. Bacot, Entomologist to 
the Lister Institute, and the late Major Sidney Rowland, of the Royal 
Army Medical Corps, Martin (1913:85) says the four salivary ducts 
open into the base of the piercer sheath; while Harrison (1916b: 209) has 
not succeeded in tracing definite connections between the salivary duct of 
the mouth parts and the ducts of the glands. Sikora (1916:56) describes 
the ducts as passing into the head alongside the esophagus as far as the 
posterior end of the sub-esophageal ganglion, where they turn back, 
and through a ventro-caudal bend reach the end of the piercer sheath. 
In Pediculus vestimenti she figures the two ducts of each side as uniting 
