HEMIPTERA. 173 
long, and fully half that in width, while the males are a little smaller 
and proportionately a little narrower. Aside from the difference in 
size the sexes differ very decidedly in the markings and structural fea- 
tures upon the under side of the body. The males have a broad black 
stripe running forward from the end of the body to near the middle of 
the abdomen, as shown in figure 100, ¢. 
The females have no indications of this stripe, but the black, broken 
band of the upper side of the terminal segment extends slightly 
around on the under side. The most important character, however, is 
the presence of two little brush-like organs on the next to the last seg- 
ment, as shown in figure 100, d. 
The head is bluntly rounded in front, nearly as broad as long, and 
with the antenne situated at the sides midway from the posterior to the 
anterior borders; behind these are located slight eminences upon which 
may be found the small eyes, which are seen with considerable difficulty. 
At the front of the head may be seen the small rostrum or beak, the 
F Gc. 100.—Hematopinus eurysternus: a, female; b, rostrum; c, ventral surface of the last segments 
of male; d, same of female; e, egg; f, surface of same greatly enlarged (author's illustration). 
end of which is usually at or near the surface, but which is capable of 
extension and retraction. The end of this beak is armed with a double 
row of recurved hooks (see fig. 100, b). The function of these hooks is 
doubtless to fasten the beak firmly into the skin of the host, while the 
true pumping organ must consist, as in the Pediculi, of a slender piere- 
ing tube, though we can see only slight indications of this tube within 
the head, and we have not seen it nor do we find any record of its hay- 
ing been seen fully extended in this species. Professor Harker says 
the rostrum can be pushed out, but his figure shows only the basal 
portion with the crown of hooks and nothing of the tubular parts 
inclosed within. 
The thorax is wider than long and widest at the posterior margin 
where it joins the abdomen. The legs project from the side, are long 
and stout, and especially adapted to clasping and clinging to the hair. 
