278 ON DEMODEX PHYLLOIDES. 
THE SKIN. 
In the abdominal region the cuticle is transversely striated, an 
appearance which Csokor attributes to segmentation. In the head 
the cuticle is not so closely applied to the underlying parts as in the 
rest of the body—a clear margin resulting, to which Megnin has 
applied the term epistome. In the thoracic region the cuticle is 
locally thickened along certain ridges which thus form a chitinous 
framework. The mesial element of this is the sternum, which gives 
off laterally four pairs of epimera, and projects also beyond the 
origin of the last pair of epimera almost as far as the anus. The 
first pair of epimera run obliquely forwards and form the boundary 
between the head and thorax. The basal joints of the four pairs of 
appendages are movably articulated to the outer thirds of the 
corresponding epimera. 
The appendages of the head are three pairs, viz.: 1 pair of 
mandibles, 1 pair of maxillae, 1 pair of pedipalpi, and an impair 
stylet-like structure between the maxillae (/y, Fig. 11), which, 
together with these, forms a piercing apparatus, while the mandibles 
and pedipalpi move chiefly from side to side, and are therefore 
masticatory. All of these appendages are attached to the cephalic 
segment. (cp, Fig. 11). On the cephalic segment are also to be 
noticed two punctiform ocelli (oc, Fig. 11), and close beside the 
contour of the pharynx (ph, Fig. 11) are two openings (de, Fig. 11) 
apparently belonging to glands in connection with the pharynx. 
The development of the cephalic segment and its appendages is 
illustrated in Fig. 1-5. First a retraction of the granular contents 
is noticeable (Fig 1), then a demarcation of the hyaline region as 
head (Fig. 2), in which an anterior notch containing a pyramidal 
outgrowth is bounded by two lateral curved processes; these are 
the future pedipalpi, while the pyramids by a division in, the middle 
line (Fig. 3), and the subsequent longitudinal division of each half 
gives rise laterally to the mandibles, medially to the maxillae 
(Fig. 4-5). 
The maxillae are curved rods 0.01 mm. in length. (ma, Fig. 11). 
Although chiefly piercing organs, they can also be moved from side 
to side. 
The pedipalpi are three-jointed, the middle joint being soft, while 
the basal and terminal joints are provided with a chitinous frame- 
