GENERAL CLASSIFICATION AND STRUCTURE. 20 
rotary motion upon the fore part of the sternum, moving toward and 
against each other, thus crushing the interposed prey. 
The palps (ps) or palpi are two organs inserted into the free end of 
the maxille, of which they are an organic part.t Each palp has five 
joints of various lengths named in order from the maxilla, (1) 
axillary, ax, (2) humeral, hu, (3) cubital, cu, (4) radial, ra, and 
(5) digital, dg. The axillary joint is the shortest of the five and corre- 
sponds to the second joint of the leg or trochanter, the maxilla being the 
equivalent of the coxa.? The 
humeral joint is much longer 
than the axillary; the cubital 
again is short, being a sort of 
knee joint. The radial is one 
and a half or twice as long as 
the above, and the digital is 
usually the longest joint of all.* 
The palps vary greatly in 
the two sexes. In the female 
each digital, dg, ter- 
Palps. 
Seseat minates like the foot 
alee and is usually armed 
with a well developed 
curved claw (palpal claw) pec- 
tinated or serrated. These or- 
gans are prehensile, are used va- 
riously as hands or feet to hold 
and turn the prey, to dig, to 
sustain the body when suspend- 
ed upon webs, to grasp the co- Fig. 12. Male of Agalena nevia: the speckled Tubeweaver. 
coon, etc., and even to aid in et) 
locomotion. In the male the digital joint contains the genital organ; it is 
enlarged, often very greatly, into a bulb whose structure is complicated and 
subject to great specific variations. (Fig. 12.) It is always more or less 
covered on top by a plate, which may be distinguished from other parts 
by a more or less dense pubescence scattered upon the superior surface and 
1 On account of the curved process upon the top of each maxilla whose convexity is 
toward its fellow, the palp may be said to issue from the side instead of the end of the 
maxilla, 
2 Westring, “Aranes Svecis,’ Termini Technici, page 11. 
® 7 have adopted the terminology of Walckenaer, which is followed also by Blackwall 
and Cambridge. That of Westring is (in the same order-as above): (1) basal, (2) femoral, 
(3) patellar, (4) tibial, (5) tarsal. The analogy between this terminology and that of the 
legs, perhaps has some advantage to the memory, but the Waleckenaer names appear to me 
to be preferable, as being quite distinctive, and thus preventing confusion with names given 
to the joints of the legs. 
