ON DEMODEX PHYLLOIDES. 279 
work. which projects on the terminal joints into three inwardly- 
directed hooks. 
The mandibles are 0.04 mm. in length, and in form resemble a 
pair of shears with rounded points. (md, Fig. 11). 
The oesophagus is short, leading directly into the stomach, which 
occupies the whole of the thoracic cavity, and is possessed of rudi- 
mentary caeca answering in position to the appendages, which give 
the stomach a wavy contour when seen from the side. (Fig. 9). 
The anus is close behind the sternum. 
In accordance with the views of Leydig, the refractive corpuscles, 
which are to be seen towards the posterior end of the body in the 
adults as well as in all stages of development, are regarded as urinary 
concretions. 
A rudimentary tracheal system is present, which is represented in 
Fig. 10. No stigmata have been made out. Between the longi- 
tudinal tracheae are two reniform bodies which Csokor is inclined to 
regard as central organs of circulation. 
Csokor studied the locomotion of the Demodex in oil on a hot 
stage. He found that the movements of the mites became very 
lively with increased temperature, and is inclined to attribute non- 
success in experiments as to transference to the absence of a suitable 
temperature for encouraging locomotion. Pedipalpi, head and legs 
are all active in locomotion ; the head is capable of lateral as well as 
vertical movement ; at a high temperature, also the abdomen may 
move upon the thorax so as to form an angle with it. The legs are 
3-jointed, (Coxa, Tibia and Tarsus ; see Fig. 11), but only the two 
latter take part in locomotion, the tarsus being capable of invagina- 
tion into the cavity of the tibia. Each tarsus terminates in five 
equally long claws. 
One of the most important of Csokor’s results is the establishment 
of three ecdyses or moults which take place (1) between the egg 
and the six-footed larva (Fig. 2); (2) between the six and eight- 
footed larva ; and (3) between the latter and the adult. 
4.—OccURRENCE AND Mope oF LIFE. 
Under this heading Csokor mentions that in the smallest tubercles 
50—60 mites may be reckoned, in the larger 500—1,000. The 
cast-off cuticles are found towards the centre of the tubercle, the 
younger stages towards the duct of the gland, and the adults 
