THE SENSES AND TITEIR ORGANS. 



297 



time when, having deposited the eggs within the little circular patch, 

 she rolls the cover around thein into a ball, and then attaches the ball 

 to her spinnerets. This is undoubtedly the universal method with spiders 

 that carry about their egg sacs. The cocoon covering is first spun upon 

 some surface, the eggs enclosed, the ball prepared, and the last act is attach- 

 ing it to the spinnerets. 



Of course, during this process, a spider whose eyesight is so good that 

 it can perceive its prey at a distance of several inches, must of necessity 

 have seen its cocoon. It would be impossible for us to reach any other 

 conclusion. The confusion in maternal recognition and selection of her 

 offspring cannot, therefore, be accounted for by defective sight. 



Among the Theridioid spiders is a large group of species which Black- 

 wall has placed under the genus Walckenaera, which present some re- 

 Bye markable peculiarities in the location of the eyes. These are 

 Turrets, ^listributed on the anterior part of the cephalothorax, which 

 sometimes in females and usually in males is remarkably ele- 

 vated. The drawings here presented (Figs. 289-293) are taken from Black- 

 wall's descriptions of 

 Walckenaiira acumina- 

 ta, ' and represent one 

 of the most remarkable 

 of those turret like de- 

 velopments of the ca- 

 put for the reception of 

 eyes.''^ The length of 

 the female (Fig. 292) 

 is about one-seventh 

 of an inch. The sexes 

 are similar in color, but 

 the male (Fig. 289) is 

 smaller than the fe- 

 male, and the anterior 

 prominence of its ceph- 

 alothorax is much more 

 elongated and slender, 

 measuring about one- 

 twentieth of an inch in 

 length. This eye tur- 

 ret is elevated vertical- 

 ly and dilated near the middle and at the apex (see Figs. 290, 291), the 

 latter dilatation being separated by a transverse groove into a superior and 

 inferior segment, both of which are rough, with short, strong hairs. On 



Walckeiiiicra acuiuiiiatu. 



Fui. 289. Male. Fig. 290. Eye turret of male, greatly enlarged ; front 

 view. FiCJ. 291. The same, side view. Fio. 292. Female. Fici. 293. 

 Same, side view of ceplialotliorax, witli outline showing natural size. 

 (After Blackwall.) 



" Spidera Gt. Br. & Ir., pi. xx., Fig. 203. 



^ See also Mr. E. Simon's Arachnides do France, \'ol. V., ]>art III. 



page sa). 



