GENERAL CONSIDERATIONS. 89 



GENERAL CONSIDERATIONS. 



From the foregoing lists it will be seen that Mayfield's Cave contains 

 practically all the cave inhabitants and lacks very few of the true cave 

 forms found in any Indiana cave. Hence it appears that a small cave 

 like Mayfield's affords practically the entire cave fauna of a cave region. 



The list of species from Mayfield's Cave is much larger than all other 

 lists from Indiana caves. This increase in number of species in itself 

 is not significant, however, except as indicating that very many species 

 may be found in caves occasionally. Those added to former lists are 

 principally species which are only incidental and temporary cave 

 residents. 



The permanent and true cave species form but a small part of the 

 entire cave fauna, while visitors, strays, and temporary residents form 

 about 77 per cent of the life of the cave. Visitors and temporary residents 

 do not ordinarily breed in the cave, and do not often go into the remote 

 portions of the cave, where there is absolute darkness and where there 

 are constant conditions of temperature and moisture. Hence they are 

 not a part of the real cave fauna and are given little consideration in 

 this discussion. Nevertheless they are interesting and significant in 

 that they show that there is no hard and fast line between cavernicolous 

 and non-cavernicolous forms. In Mayfield's Cave and about its mouth 

 there are represented all gradations between animals whose habitat 

 is in the open in the woods near the mouth of the cave and other forms 

 (e. g., Anopthalmus tennis, Quedius spel&us, and Phanetta subterranea) 

 which are well adapted for cave existence and probably do not occur 

 outside of caves. 



True cave forms are not necessarily confined to absolute darkness. 

 They always live in dark places, but may wander away from the absolutely 

 dark portions of caves into twilight or even outside of caves. The blind 

 isopod Cascidotea stygia is common in caves throughout Indiana and 

 Kentucky and is apparently nearly subterranean in habit, yet it 

 is not confined to this mode of existence. It has been found under 

 stones in streams, and in wells, springs, and drains in Virginia, Illinois, 

 Kentucky, and Indiana. The Ceuthophilus stygius seems fairly well 

 adapted to cave life, but besides being found in caves, occurs in cellars and 

 about wells. Sinella cavernarum, so common and abundant in Indiana 

 and Kentucky caves, occasionally wanders from darkness into dim twi- 

 light at the mouth of Mayfield's Cave, but has not been taken in full 

 daylight, and probably could not stand conditions less constant than those 

 of a cave. Banks (1893) found Scotolemon flavescens, an arachnid pre- 

 viously known only from Indiana caves, under stones on the Virginia 

 shore of the Potomac near Washington, D. C. , which does not differ from 



