14 
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 
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. 6b). The function of these hooks is 
Fic. 6.,—Hematopinus eurysternus; a, female; b, rostrum; c, ventral sur- 
face. last segments of male; d, female; e, egg; f, surface of egg greatly 
enlarged. (Original.) 
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 hav- 
ing been seen fully extended in this species. Professor Harker says 
the rostrum can be pushed out, but his figure shows only the basal por- 
tion 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. 
An extra provision for this purpose consists of a double plate having 
fine transverse ridges in the basal joint of the tarsus. This structure 
appears to have been first described by Professor Harker (Agricultural 
Students’ Gazette, vol. 1, p. 162). The abdomen differs greatly in form 
and size, according to the degree of distention, which accounts for the 
discrepancies in the different figures of this species. It may be called 
flask-shaped and more or less flattened according to the amount of mat- 
ter contained in it. There is a row of horny tubercles along each side 
and a row of chitinous plates along each side of the upper surface of 
the abdomen. The spiracles are located in the tubercles at the sides, 
and there is one to each of the last six segments omitting the terminal 
one. In color there is some variation, as would be surmised from a 
comparison of descriptions by different authors. The general color 
