1 86 NORMAN E. MCINDOO. 



were likewise experimented with. Some of these were negatively, 

 others positively phototropic. The kind of phototropism de- 

 pends on the natural environments of the specimen. It was 

 observed that the specimens collected on this trip always pre- 

 ferred the dark end of the vials. All true cave spiders are more 

 or less negatively phototropic. The distribution and number 

 of all true cave spiders are controlled by even temperature and 

 the abundance of food. They probably have no enemies other 

 than themselves and are rarely seen righting. They soon die 

 outside the caves unless kept in a saturated atmosphere. 



