210 
HERBERT OSBORN. 
grounds to apply the term equi to our common form. W< 
will therefore introduce descriptions and comparisons of th( 
two forms, and adopt, for the present at least, and on the 
authority of Piaget, the names given in his “ Les Pediculines.’ 
Trichodectes pilosus , Giebel. (Plate II., Fig. 7.) 
This, according to Piaget, is the form originally designatec 
by Linnaeus as equi , and which, if that is correct, was the 
basis for a name which has been widely used to designate thf; 
biting lice of the members of the horse family. The origina 
reference dates back considerably more than a century, anc 
doubtless, the insect was familiar many centuries before that 
as the horse and ass have been too familiar as domestic ani 
mals to allow the parasite common to them escaping entirel} 
the notice of man. 
According to Piaget this occurs upon both the ass and th(| 
horse, while the following species he has found only on th( 
horse. 
We have not been fortunate enough to secure samples 0 
this form, though we have the other in great abundance, S( 
we are compelled in describing to depend upon the excellen 
description and figures of Piaget, the latter being reproducec 
(in Fig. 7) for comparison. The head in this form is shorte 
and less rounded in front, that of the male being still lesi 
rounded than the female, while the abdomen is more slende: 
and tapering. The transverse bands are also represented a: 
less conspicuous. Perhaps the most striking point, however 
is the position of the antennas, which stand well forward 01 
the head, so that the front border of the head and base of th( 
antennas are nearly in line. 
The habits of the species and the remedies applicable to 
it are naturally identical with those of the other relateq 
species. 
Trichodectes parunipilosus , Piaget. (Plate II., Fig. 6). 
While it does not seem possible that all the writers pre 
vious to Denny should have overlooked this form, which ap 
pears to be the more common one, at least on the horse, i 
