17 
under the name of Pediculus oxyrhynckus, which name was Latinized by 
Burmeister to tenuirostris. This designation has been followed by 
Giebel and Piaget, but why the earlier name of Linnaeus was dropped 
we fail to discover. It seems more proper to retain the name given by 
Linnaeus. 
Denny describes and figures the species and says that it has been 
found only on the calf. Giebel also figures and describes it, giving a 
very characteristic figure, though deficient in some details. Piaget 
admits the species provisionally, but questions it being separable from 
eurysternus from the fact that descriptions have been based only on 
female specimens or on those in which the sex was not distinguished, 
and he seems to think it probable that immature specimens of eurys- 
ternus may have furnished the basis for this form.* 
From material in hand there can be no question whatever as to there 
being a distinct form corresponding with the descriptions above cited, 
and while there are some details still to be cleared up we propose to 
show as fully as possible the differences. While our material does not 
include any specimen that can be recognized as a male, it does include 
enough specimens of the early stages and females of both this species 
and the eurysternus to entirely set at rest any question as to immature 
forms of eurysternus having been described as vituli or tenuirostris. 
In this species the body is about one-eighth of an inch long and not 
more than one third of that in width (see Fig. 
7). The head is long and slender, the anten- ^f^Aj^v 
na3 set near the middle each side ; there is A |Bt Jr* 
but a very slight protuberance behind the r-^Jm^^ 
antennas and no eyes visible. The head sets ~^Cyy 
well back into the thorax, forming an acute 
angle behind ; the thorax is longer than wide, 
and has a distinctly showing spiracle above ' % 
the second pair of legs; the abdomen is elon- W£k \^- ^ 
gate, without chitinous plates and devoid of -Aj-^-y^ \ 
any tubercles along the sides : the terminal V 
segment is also devoid of black horny band ; ^~ " 
the brush-like organ on the under side of the 
abdomen (see Fig. <) is slender, while the and under surface of 1 
, . , . , ., of female, showing brush like ..r- 
termmal segment is set with numerous rather gans. (Original.) 
long hairs. 
In all of these points it will be observed there is a distinct difference 
from eurysternus. The brush-like organ on under surface oi' the abdo- 
men, common to females of related species and which is wanting in young 
specimens of all species, must be taken as distinct evidence of the ina- 
* Since the preparation of this section and the figures illustrating the species 1 have 
seen the supplement to Piaget's Les Pedicu lines and find thai he now admits this as 
a good species and gives a figure of the female, without, however, any special ilt\ji!s 
of structure. 
21122— Xo. 7 2 
