208 INSECTS AFFECTING DOMESTIC ANIMALS. 
Trichodectes pilosus Giebel. 
This, according to Piaget, is the form originally designated by Lin- 
neus as equi, and which, if that is correct, was the basis for a name - 
which has been widely used to designate the biting lice of the members 
of the horse family. The original reference dates back considerably 
more than a century, and doubtless the insect was familiar many cen- 
turies before that, as the horse and ass have been too familiar as 
domestic animals to allow of the parasites common to them escaping 
entirely the notice of man. 
According to Piaget this occurs upon both the ass and the horse, 
while the following species he has found only on the horse. 
We have not been fortunate enough to secure examples of this form, 
though we have the other in great abundance, so we are compelled in 
describing to depend upon the excellent descrip- 
tion and figures of Piaget, the latter being repro- 
duced here for comparison. The head in this 
form is shorter and less rounded in front, that 
of the male being still less rounded than the 
female, while the abdomen is more slender and 
tapering. The transverse bands are also repre- 
sented as less conspicuous. Perhaps the most 
striking point, however, is the position of the 
antenne, which stand well forward on the head, 
so that the front border of the head and base of 
the antenne are nearly in line. 
The habits of the species and the remedies 
applicable to it are naturally identical with those 
of the other related species. 
7 pn na ‘i 4 = 
Bi, . “> ToT * = 
Me eed as te = 
2 ens 
Trichodectes parumpilosus Piaget. 
Fig. 133.— Trichodectes par. 
umpilosus — enlarged (au- While it does not seem possible that all the 
shia ry ego writers previous to Denny should have over- 
looked this form, which appears to be the more common one, at least 
on the horse, it may be true that Denny was the first to give it a thor- 
ough description and careful drawing. He speaks of it as common on 
the horse and ass, but Piaget says he has never found it on the ass, 
and there is of course a possibility that Denny did not distinguish 
between this and the preceding species. 
In this species the head is decidedly rounded in front, the antenns 
inserted well back, so that the head forms a full semicircle in front of 
the base of the antenne. The abdomen is more slender and tapering 
than in scalaris, but less so than in pilosus, as Shown in Piaget’s figures. 
The color is much the same as in the allied species, the head, thorax, 
and legs being a bright reddish brown, or chestnut, and the abdomen 
of a dusky yellowish color, with about eight transverse dusky bands 
occupying the central or anterior portions of the segments and extend- 
