Peckham—Revision of the Attidce of North America. 455 
figures will serve to distinguish them. The variation in the 
spines on the tibia of the second leg is sometimes useful. 
The spiders of this genus are rather small, rarely over 7 mm., 
and have, with some exceptions, the following characteristics: 
Cephalothorax rather high and convex, widest in thoracic part, 
highest at dorsal eyes, a little wider below than above. Front 
eyes large, slightly separated, in a curved row. Second row 
halfway between the others, or a little nearer the first. Eye- 
region 1-4 to 1-3 wider than long, wider behind than in front, 
occupying 2-5 of cephalothorax. Body not smooth but not very 
hairy, legs not lineate with dark, first and fourth longer than 
second and third, first pair not much the stoutest (except in 
castaneus) and not fringed, although there is, rarely, a brush 
of hairs under tibia I. Males often bronze or yellow with bright 
white markings, females usually less conspicuous, gray, brown 
or yellow with pale indefinite marks. The species are numer¬ 
ous and widely distributed and they resemble each other closely. 
Key to Males. 
( Falces horizontal . prosper 
1 j Falces oblique* . 2 
2 \ Falces long and slender . limbatus 
} Falces wide in proportion to their length. 3 
o $ Palpus with a blunt heavy tube ... montanus 
( Palpus with a fine pointed tube . 4 
( Falces with white bars in front; Arizona and Pacific 
4 j slope . imperialist 
( Falces not barred with white . 5 
f Tube of palpus bent; white bands high up on sides of ab- 
5 ! domen . militaris 
i Tube of palpus straight; white band low down on sides 
l of abdomen .. floridanus 
g f Tibial apophysis bifurcated . 7 
\ Tibial apophysis simple . 8 
* Since in militaris, montanus and floridanus the falces are sometimes 
oblique and sometimes vertical, these species are taken out under both 2 and 6. 
t Imperialis has a characteristic marking on the face, there being divergent 
white bands on the clypeus parallel with those on the falces. The tibial 
apophvsis is also distinctive, while in militaris the shape of the falx is 
peculiar. These points are brought out in the figures. 
