WILLIAMS: BOOPIIILUS ANNULATUS. 
315 
Henking ( 82 ) found that in sectioning Trombidium the fat was 
the disturbing element and he recommends imbedding that species 
in paraffin, cutting the animal in half, dissolving the fat out with 
ether, and then reimbedding and sectioning as usual. 
Given satisfactory sections, one may proceed with any of the regu¬ 
lar processes of staining and mounting. Mayer’s alcoholic cochineal, 
old formula, gave good results. Ideidenhain’s and Delafield’s haema- 
toxylins were also used. Henking used Grenadier’s borax carmine 
for Trombidium. 
The work of Pagenstecher (’ 61 ) gives a comprehensive review 
of the literature on Ixodes up to that time. As a complete biblio¬ 
graphy of the tick literature is given by Salmon and Stiles (: 02) 
in the “Report of the Bureau of animal industry for 1900,” only 
those papers directly referred to will be included in the present 
bibliography. 
External Form. 
The adult, gravid female Boophilus is about half an inch in length 
and rounded in body. Its legs seem short and its capitulum seems 
very small, though it is much larger than that of the male. There 
is a small shield or scutum back of the capitulum on the dorsal side. 
The genital pore is on the ventral side of the body in the midline 
between the coxae of the first pair of legs. Behind the fourth pair 
of legs are the two stigmata or openings of the tracheal system. In 
the ventral midline and back of this transverse plane lies the anal 
opening which is closed by a sort of valve. 
The male is much smaller than the female and flatter in body. 
Its beak or haustellum is actually shorter than that of the female, 
though the proportions make both this and the legs seem longer. 
The shield in the case of the male covers nearly the whole dorsal 
surface. There are also four chitinous projections on the ventral 
side at the posterior end of the male animal which do not appear on 
the female. 
Fig. 1 (pi. 18) is drawn from a natural-sized photograph of a few 
eggs, a male, and a gravid female, to show their relative sizes. 
In fig. 2 (pi. 18) the beak of a small female is drawn as seen from 
the dorsal side. Just above it is the piece of cowhide which came 
off with the tick. The haustellum or beak which is composed of 
