522 Wisconsin Academy of Sciences, Arts and Letters. 
behind. Front eyes bulging forward, and looking down, in a 
straight or slightly curved row, the middle less than twice as 
large as the lateral. Second row halfway between the others. 
Third row narrower than the cephalothorax. Sternum longer 
than wide, narrowed behind. Coxae I separated by width of 
labium. Labium about as wide as long or (pulex) longer than 
wide. Falx with one tooth on lower margin. Legs not conspic¬ 
uously fringed nor enlarged. Abdomen wide and short. Tube 
of male palpus, short and curved.* 
Simon describes this genus as having the third pair of legs 
much longer than the fourth, but this does not hold true of Am - 
erican species, in which the fourth leg is somewhat the longer, 
except in acerbum, where the 8 is 3412 and the 9 3412. The 
third and fourth legs are longer than the first and second in 
both sexes. 
HABROCESTUM ACERBUM n. sp. 
Plate XLIV, figs. 1—lc. 
Length, 8 2.5 mm., $ 4.5 mm. Legs, 8 3412, $ 3412. 
The tibiae of the first legs, in both sexes, have the spines in two 
pairs below, and one anterior lateral, and the metatarsi of the 
first and second have two pairs and laterals. The tibia of the 
second has two pairs and one anterior lateral in the male, and 
one pair and two serially below, and one anterior lateral in the 
female. 
In this species there is a very great variation in the distribu¬ 
tion of the light and dark coloring. In the male the cephalo¬ 
thorax is reddish-brown with a more or less distinct white band 
on each side of the cephalic plate from the lateral to behind the 
dorsal eye, and a transverse whitish band behind the dorsal eyes. 
There is a white marginal band. The clypeus is dark under the 
middle eyes and white under the lateral. The abdomen has a 
black band at the base, and above this a wider band of white 
* The only species of Pellenes that has a short curved palpal tube is 
P. limatus. 
