GENERAL CLASSIFICATION AND STRUCTURE, v5) 
clares that the first leg is the longest, then the second leg, then the fourth 
leg, and lastly the third leg. When two pairs of legs are of equal length 
the numerals expressing them are united by the sign of equality; thus, 
12—43 indicates that the second and fourth legs are of equal length.! 
For the most part the third leg is much the shortest of the four, and the 
first pair decidedly the longest. This rule, however, varies in certain 
genera, as Acrosoma, in which the fourth pair is as long as, or longer 
than the first, a variation which seems to be adapted to the peculiar form 
of the spider. The males have legs longer and slighter than the females, 
and in some species haye a special armature in the shape of a comb of 
stout spines upon the tibia of the second pair, which probably serves as ¢ 
clasping organ in the act of pairing. 
The legs have seven joints, which are arranged in the following order, 
counting from the point of union with the sternum: First, the coxa (ex, 
Fig. 18), the short joint which unites the leg to the body. 
It is partly concealed beneath the cephalothorax, and 
sometimes carries short, pointed processes. Second, the 
trochanter (tch), a minute joint which really serves for 
the articulation of the leg upon the body, the coxa being 
fixed, Third, the femur (fm), usually the longest and 
stoutest joint of all. Fourth, the patella (ptl), which 
nearly corresponds in length with the coxa, and Serves aS . 14 moot of see 
a sort of knee joint. Fifth, the tibia (tb), whose length — insularis. s.ci, superior 
is usually a little less than that of the femur. Sixth, (pyipe pe sorciame 
the metatarsus (mtr), the penultimate joint, which ap- ict, inferiorclaws; au.cl 
proaches the length of the femur, is commonly longer M&{Et¥clewsuponthe 
than the tibia, but much slighter. Seventh, the tarsus 
(tr), the ultimate joint, which is usually shorter than the metatarsus. The 
last five of these.joints are armed with a great number of spines, bristles, 
and hairs, which are placed more freely along the inner surfaces of the 
legs, and thus are disposed for the greatest advantage of the animal in 
manipulating its prey, embracing its mate, or fighting its enemies. They 
are also used in spinning the snare. 
Orbweavers haye three strong, genuine claws upon their tarsi, of which 
the two superior are pectinated, and (with rare exceptions) the inferior is 
armed with two close and blunt comb teeth (cb.th). The supe- 
rior claws are of equal size, placed side by side. The inferior 
claw is smaller than the others and is below them, bent down 
near the base. The extremity of the tarsus is always provided with two 
or more auxiliary claws (au.cl).2 One of these, a strong spine, has the 
Tarsal 
Claws. 
'T have taken this formula as more convenient for expression in type. In most authors 
the equal members are joined by a bracket above, thus: 1 2 4 8. 
? Thorell, European Spiders, page 47. 
