COURTSHIP AND MATING 71 



has been carried to a ridiculous extreme. These tiny males are vir- 

 tually immune to the attacks of the great females, being far beneath 

 the usual size of the latter's prey. Tiny insects have much the same 

 immunity, and are tolerated when they crawl over a spider's body 

 and left untouched when they are caught in its web. Great reduc- 

 tion in size doubtless represents an orthogenetic development that 

 has nothing to do with the needs of the sex itself, but persists once 

 it has started. It also brings with it other problems, since the males 

 become sexually mature weeks in advance of the females and must 

 live until the females mature. 



The males possess the two pedipalps with the complex sexual 

 organs at the end; these organs have become wonderfully specialized 

 to aid in the pairing. The legs are also frequently armed with spurs 

 or with rows of modified and enlarged spines that aid in clasping 

 the female or in holding her chelicerae or appendages. The taran- 

 tulas, trap-door spiders, and many of the primitive true spiders have 

 two prominent processes on the front legs to catch the appendages 

 of the female. The elongated chelicerae of Tetragnatha and Pachy- 

 gnatha are used to grasp those of the female. Among aerial sheet 

 weavers, the Linyphiidae, we find a tremendous group of species in 

 which the heads of the males are specialized in divers peculiar ways. 

 There are pointed or rounded spurs armed with curious setae, great 

 rounded lobes, long, thin processes, prolongations of the clypeus or 

 front; and the eyes are often carried to the tops or sides of these 

 eminences. There is little doubt that these spurs are of significance 

 in the mating of the species. In some of these spiders, it is known 

 that the female fixes her chelicerae in the tiny pits on each side of 

 the head lobe, and thus orients the male for mating. 



Sexual dimorphism also manifests itself in profound differences 

 in color pattern and intensity. The carmine legs and shining black 

 body of At y pus bicolor, the large purse-web spider, far outshine 

 the pleasant brown tones of the female. The male tarantulas have a 

 darker body and often have the abdomen set with long golden or 

 reddish hairs. Among the true spiders, the males are much more 

 varied and usually more handsome than their mates. This is espe- 

 cially true of the jumping spiders, which in the tropics display a 

 spectrum of color, the most brilliant hues of which are restricted to 

 the males. In many instances, the sexes are so different in appearance 

 that they were formerly regarded as being of distant species. 

 Among certain of the sedentary spiders the sexes are somewhat 

 more equal from the color standpoint; and of the spiny-bodied 



