6 AURIVILLIUS, A NEW GENUS OF HARPACTICIDA. 
united in one piece, a little broader than the preceding 
and following segments. Furca as long as each of the nearest 
joints and bearing on each side, at the apex, only a single, 
long, non-ciliated seta, a little more than half as long as the 
body. Each branch of the furca bearing also on its outer 
margin a short, but rather stout, inarticulate seta, reaching 
to or slightly beyond the distinetly marked basal joint of 
the tail-seta, and on its upper margin, just within the place 
where the small seta is fixed, a similar finer triarticulate one. 
There are also some small spines round the base of the tail-seta. 
The anterior antenne present a different structure in the 
two sexes. Male: (Pl. I. Fig. 4.) Antenne consisting of 
eight joints; the fourth of these bearing the sword-shaped 
appendage, the first of the following four joints very short, 
and the third swollen on its inside; last joint long, of 
equal breadth throughout, having two terminal setze, of which 
one is very long and simple, the other shorter and trifid. 
Moreover there are several sete on the outer margin of the 
second, third and fourth joints; one on the same margin of 
the sixth and seventh, one in the middle and two on the 
inner margin of the last joimt. Besides the ordinary sword- 
shaped appendage at the distal end of the fourth joint, there 
is also a similar one at the same end of the third. At the 
base of the fourth joint there is a setiferous tubercle which, 
when the antenna is extended, covers the end of the third 
joint. — Female: (Pl. I. Fig. 5.) Antenn&e differimg from 
those of the male by being shorter and of a much more 
slender structure, and by the four last joints being of almost 
equal length and of the usual shape. Fourth joint destitute 
of the tubercle and the sword-shaped appendage of the male, 
seventh joint having at its apex the longer terminal seta much 
shorter. The other setx almost similar to those of the male. 
The posterior antenne (PI. I. Fig. 6.) two-joimnted and alike in 
the two sexes. First joint destitute of sete on its margins, but 
having near the middle of the outer margin some small spi- 
nes, placed in a semicircle, and a little above the middle a 
small secondary branch, scarcely reaching to its apex and 
provided with three sete. Atthe one margin of the secondary 
branch there appears a notch where the subapical seta 
is placed in the genus Canthocamptus WEstwoop. Second 
joint broader above than at its base, having its distal end 
