EPEIRA. 



235 



apertures. These communicate with the spinning glands 

 lying in the abdomen, a complex series of glands which pro- 

 duce threads of various kinds, according to the requirements 

 of the spider. Further forward on the ventral line of the 

 abdomen opens the genital aperture and on either side of 

 it the single pair of stigmata leading into the pulmonary 

 sacs. Lastly, just in front of the spinnerets there is a small 

 median aperture leading into four trachece. 



The integument of the spider consists of a thin cuticle 



over the abdomen, thickened in the cephalothorax. The 



whole surface is more or less covered with 



fine hairs which extend down to the tips of 



the legs. The dorsal anterior surface of the cephalothorax 



Fig. 156. — Longitudinal Sagittal Section through Epeira 

 Diadem ATA ( 9 ). (Semi-diagrammatic, after Leuckart.) 



Heart. 



Lateral Eye. 

 Median 



Eyes. 

 Lateral 



Eye \ 



Poison - 



Gland. 



Mouth. I . ^ 



Caecum of Stomach. ^ 9. 



Dorsal 

 Blood-vessel, 



Cloaca. 



Spinning Glands. 

 Ovary. 

 Genital Aperture. 



is smooth and bears six eyes which are of the simple 

 type. Four are arranged in a small square and the other 

 two laterally. 



The mouth leads up a small tubular pharynx and a short 

 oesophagus into the large *' sucking " stomach. The walls of 

 Alimentary ^^^^ organ can be drawn outwards by strong 

 muscles, causing powerful suction. The true 

 stomach is small and expands into long cceca which end 

 blindly towards the bases of the legs. The intestine 

 is narrow and leads through the "waist" into the 

 abdomen. Here it swells into a sac, receiving the 



