1909.] ECTOPARASITES OF THE RED GROUSE. 317 
The Alimentary Canal. 
Grosse has described just within the mouth a dorsal and a 
ventral piece of a “schlundskelet.” Unless the lyriform organ, or 
“ @sophageal sclerite,” represents the ventral] piece, this structure 
is not evident except in sections. 
The esophagus is a simple tube with muscular walls which 
traverses the posterior part of the head and the thorax (Pl. XL. 
fig.12). Soon after it reaches the abdomen it gives off a blind 
pouch or crop, which is always choked with feathers and forms 
the conspicuous black patch which shines through the wall of the 
abdomen. The walls are very muscular, both longitudinal and 
circular muscle-fibres being conspicuous. It usually lies near 
the middle line, but slightly obliquely, and pointing posteriorly 
to the right. Behind the point where the crop is given off the 
stomach or chylific ventricle passes backward, lying to the right 
of the crop. At the posterior end of this the four Malpighian 
tubules arise, and then there follows a short intestine in which 
usually masses of undigested feather-fragments are to be seen. 
The intestine is short and ends in a ring of six almost spherical 
(? glandular) bodies (Pl. XL. fig. 12). Each of these seems to 
consist of a single gigantic cell, and the whole is very richly 
supplied with tracheez. These bodies closely resemble similar 
structures found in the rectum of many Diptera, ¢. g., the blow- 
fly and the mosquito. Behind them there is a short rectum, 
which ends in an anus situated beneath the terminal plate. 
Numerous muscles run from the body-walls of the last two 
segments to be inserted into the rectum and doubtless act as 
divaricators. 
The food consists of feather-barbules; a sample of it taken 
from the crop is shown in Pl. XL. fig. 13. 
The Exeretory System. 
This system consists of (a) the Malpighian tubules, and 
(6) the Fat-body, in which nitrogenous waste matter is often 
stored away. The Malpighian vessels are four in number; they 
arise at the anterior end of the intestine, and near the base each 
swells into an oval vesicle (Pl. XL. fig. 12). The tubules are 
long, as long almost as the body, and are coiled away amongst the 
viscera. 
The fat-body is very definitely arranged, there being paired 
pouches of it at the sides of each segment (Pl. XLI. fig. 16). In 
the cavity of these pouches are five collections of oval structures, 
which may be the five pairs of ovarian tubules, showing the ova, 
but somewhat similar structures occur, in equal numbers, in the 
taale abdomen. 
