^7 
The capitellum is provided vdth paired sharply pointed maxillse, 
and it incases for a portion of their length the paired mandibles, which 
are pro^dded with didactylous pinchers in the female. In the male 
the}" are modified to form ^‘clasping’’ organs. The maxillary paljps 
are attached, one on either side, to the lateral aspect of the capitellum. 
They serve as sense organs, eyes being absent, and are composed of 
five articles. Two stigmata are present, vdth a prolongation forward 
of a tubular peritreme. The a7ius is located in an anal plate, the 
anterior margin of which is convex and the posterior prolonged into 
a large spine. In the female the sexual aperture is located in the 
mid-line of the body in the genital plate, near the posterior border 
of the sternal plate. In the male the genital pore is in the center of 
the sternal plate. The body of the adult female measures from 1.1 
to 0.9 mm. in length by 0.7 to 0.6 mm. in breadth. The male is 
two- thirds the size of the female. 
INTERNAL ANATOMY OF LELAPS ECHIDNINUS. 
Technique. — The difficulty of dissecting so small an object as this 
mite, especially as it is covered vdth hard cliitinous plates, is very 
considerable. With the aid of fine needles, teased preparations can 
be made, a small per cent of which vdll be fairly successful. In the 
main, serial paraffin sections must be relied upon. The fixatives 
used were 5 per cent formalin, 80 per cent alcohol containing 5 per 
cent of formalin, and alcohol in various strengths. In addition, 
a fixative composed of 3 parts chloroform, 2 parts glacial acetic acid, 
1 part saturated solution of bichloride of mercury, and 6 parts abso- 
lute alcohol was employed. In some instances soaking in a solution 
of 2 per cent celloidin preceded the embedding in paraffin. 
Some satisfactory sections parallel to the ventral surface were 
made without softening the chitin, since none is encountered by the 
knife. For other sections in which the cliitinous plates are to be cut, 
the mites, previously exposed to the action of fixatives, must be treated 
with a softening solution. For this purpose Labaracpies solution 
in varying dilutions was employed. The length of time of its action 
.depends upon the strength of the reagent and can only be determined 
by trial. It was found preferable to merely soften the chitin rather 
than to completely remove it. In the latter event, air bubbles form 
in the body ca^dty, wliich greatly interfere with subsequent dehy- 
dration and embedding. 
The sections, affixed to slides vdth Mayer’s albumin fixative, 
were stained with lYeigert’s iron hematoxylin. 
Anatomy or the head region. — The capitellum is prolonged ante- 
riorly to form the mouth parts. The dorsal anterior border forms a 
serrated projection, the epistome. The mandibles, which are double 
