448 Wisconsin Academy of Sciences, Arts and Letters. 
is a little wider behind and occupies 2-5 of the cephalothorax. 
The anterior row is straight and the middle are not twice as large 
as the lateral eyes, from which they are slightly separated. The 
eyes of the second row are nearer the first than the third. The 
third row is not as wide as the cephalothorax at that place. The 
sternum is one and one-half times longer than wide, truncated 
in front and rounded behind. Lip longer than wide. There 
are two pairs of bulbous hairs on the under face of the posterior 
half of the tibia of the first pair in both sexes. These hairs are 
peculiar to the genus and distinguish it from all other genera 
in the United States. The teeth on the lower border of the 
falces are exceedingly variable; in some the tooth is compound, 
in others single and in a few there are several teeth. Even the 
two falces in the same specimen are occasionally unlike. The 
genus is found in all the Americas. 
In this genus are included several species that have been re¬ 
ported under different generic names.- These are Attus elegans 
Hicolet, Attus sylvanus Hentz $ (= Attus retiarus H $ ), At¬ 
tus puerperus Hentz (= Attus agrestis P.), Alcmena pallida 
C. K. (=Marpissa Branickii Tacz). Thiodina takes prece¬ 
dence of Colonus E.O.P.C., which was founded upon sylvanus 
H., which he calls puerperus. He included one other species, 
crucifer. 
Thiodina is represented in the United States by only two 
species, sylvana and puerpera. In 1888 we described sylvana 
under the name puerpera. At that time we believed that we 
had but one species, the two being so nearly alike that we took 
them to be identical, including sylvana as a synonym of the so 
called puerperus, and also wrongly including A. pallida 0. K. 
and M. Branickii Tacz. Mr. Banks first called attention to 
the slight but constant differences which characterize the two 
species. In our error regarding sylvana and puerpera we were 
followed by Simon and F.O.P.Cambridge. 
