586 Wisconsin Academy of Sciences, Arts and Letters. 
Small thick-set spiders, with the abdomen not much larger 
than the cephalothorax. 
Cephalothorax low, flat, slightly dilated behind the middle, 
with sides vertical in front and slightly rounded behind. Thor¬ 
acic part truncated and hollowed behind. Eye-region scarcely 
shorter than thoracic part, 1-3 wider than long, slightly wider 
behind than in front. Front eyes touching, in a straight row; 
second row nearer first than third; dorsal eyes as large as lateral 
eyes of first row, further from each other than from lateral bor¬ 
ders, forming a row as wide as the cephalothorax at that place. 
Clypeus high, slanting backward. Ealces parallel, weak, with 
two or more teeth on the lower margin. Labium rounded, wider 
than long, or but little longer than wide. Sternum oval. Abdo¬ 
men small, the anterior end fitting into the excavation of the 
cephalothorax. 
Mr. Banks, in his Glassification of the Attidse, makes our 
Ballus Youngii the type of his genus Attidops, although Youngii 
is so close to the type of Ballus (depressus) that Mr. Emerton, 
in a letter to us, has suggested that it may be identical. We 
think that it differs enough to be a good species, but it clearly 
belongs to the genus Ballus, and hence we treat Attidops as a 
synonym. 
BALLUS YOUNGII P. 1888. 
Plate XLIX, figs. 9—9a. Plate LI, figs. 13—13a. 
VII, N. A. Attidse, p. 87. 
8 $ . Length 2.8 mm. Width of abdomen, 1.4 mm. Legs 
4123, first and second pairs stoutest. 
The whole abdomen and the upper surface of the cephalo¬ 
thorax are black; there is a scanty covering of short yellow 
hairs, which thicken, on the abdomen, to form two yellow spots 
in front, and three transverse bands further back. The other 
parts are brown, the legs and palpi with short yellow hairs. 
Col. J. J. Young, who first sent us this species, wrote of it as 
follows: “These spiders are found at this season (ISTovember) 
under the bark of trees, usually hickory and sycamore. You 
