24 AMKincAX Sl'IDICKS AND THKIR SPINNINGWOKK. 



soinotiines under the apex. This genital plate or lamina corresponds to 

 till' aj>ical i)art of the female digital, but the digital claw is entirely 

 wanting, or rudimentary and hidden liy jiubescence. The genital organ is 

 placed under the liase of the lamina. It is furnislied with processes vary- 

 ing in form, size, and nundier, and with a liook or tulie (or tubes) which 

 tit into corresponding cavities in the female organ, and transfer the semi- 

 nal lluid thereto. This peculiar formation does not appear until the last 

 movdt, when the spider is mature. Previous to that the male digital is 

 simjjly a hairy bulb. The term genital bulb is also applied to the genital 

 organ. Sometimes the bulb is qiute one with the lam- 

 ina in which it is mulilcil, in wliidi case the bulb is 

 called the clava.^ 



During the interval between tlic tliinl and fourth 

 moulting a considerable change takes place. In tlii' 

 male the extremities of the palpi swell like chd)s and 

 develop into different indentations, teeth, threads, or 

 leaves, which later on serve as transmitters of 

 Chanees ^^'*^ semen. At first the clubs are filled witli 

 semitransj)arent fluid, while the forming inner 

 organs are yellowish or brownish ; at first the skin is 

 quite soft, but soon hardens and forms a shell, which 

 turns darker by the action of the air. Inasmuch as 

 Fig. 13. Leg of Epeira tlicsc orgaus are aluiost dcvold of soft parts it follows 



magnified. Cx, coxa, .11,1. ii i 11 1 jv i; ii 



tiie joint which unites naturally that as tlie sliell cannot come on, no further 

 the leg with the ster- moulting call take iilace. 



nuni ; tch, trochanter, ^ . ^ 1 • i 



small joint by which At the time tlic palpi bcconie fully developed a 



the femur articulates ^ change takcs place also ill the female genitals; 



upon the coxa ; fra, fe- '^ " ^ fe ) 



mur; pti, patella; tb, the immediate surroundings Ijccome roughened and 



tibia : mt, metatarsus : lii ^ ^ a- i-iiii i-i 



t, tarsus; ci, claws. somewluit iiartlcned, presenting little huin2)s which serve 



l^artly as rests for the male palpi and partly as recep- 

 tacles for the semen, and is what is designated as "vulva."^ When fully 

 matured the sexes, hitherto separated, come together, and the copulation 

 takes j)lace in a different manner by different varieties.^ 



The legs of the spider are eight, symmetrically disposed, four on each 

 side of the sternum to which they are articulated. Their relative lengths 

 give one of the best characters for systematic arrangement. They 

 Lee-s '^'''"' '"""'"''■'''' l''"in the face backward as first (1), second (2), 



third lo), and fourth (-l) pairs. (Fig. 11.) The relative lengths 

 are indicated by a formula composed of the above numerals arranged in 

 the order of greatest lengths from highest to lowest, thus : 1 2 4 3 is the 

 fonnula which expresses the prevailing order among Orbweavers and de- 



' \\\'striii<r, Arancif Svccia', jiiiirt' 1l'. 



- Mi'n<;e, "Die rivusisipche Sjiiiiniii." ' 



'See Cluiiitor on " WouinL' ;iiiil .M;itiii'.' llabitis," Vol. II. 



