SHORT SIGHT OF OCELLI. 17y 



female, and, after taking the bag of eggs from her, put 

 her on a table. She ran about awhile, looking for her 

 eggs. When she became still, I placed the ball of 

 eggs gently about two inches in front of her. She 

 evidently did not see it. I pushed it gradually towards 

 her, but she took no notice till it nearly touched her, 

 when she eagerly seized it. 



I then took it away a second time, and put it in the 

 middle of the table, which was two feet four inches 

 by one foot four, and had nothing else on it. The 

 spider wandered about, and sometimes passed close to 

 the bag of eggs, but took no notice of it. She 

 wandered about for an hour and fifty minutes before 

 she found it — apparently by accident. I then took it 

 away again, and put it down as before, when she 

 wandered about for an hour without finding it. 



The same experiment was tried with other individuals, 

 and with the same results. It certainly appeared as if 

 they could not see more than half an inch before them 

 — in fact, scarcely further than the tips of their feet. 



I may also mention that they did not appear to 

 recognize their own bags of eggs, but were equally 

 happy if they were interchanged. 



On the other hand, it must be remembered that the 

 sac is spun from the spinnerets, and the Lycosa had 

 perhaps actually never seen the bag of eggs. Hunting 

 spiders certainly appear to perceive their prey at a 

 distance of at least several inches. 



Plateau has shown, in a recent memoir, that cater- 

 pillars, which possess ocelli, but no compound eyes, 

 are very short-sighted, not seeing above one to two 

 centimetres.* 



* "Rech. Esp. sur la Vision chez les Artliropocles." Bull, de 

 'Acad. Roy. de Belgique, 1888. 



