90 FAUNA OF MAYFIELD'S CAVE, 



cave specimens. Absolon (1900, 4) found that certain cave thysanurans 

 and mites were killed in a few minutes by exposure to daylight, while 

 other thysanurans and mites from outside of caves were not affected by 

 the same exposure. Hence while some typical cave forms wander out- 

 side of caves into other dark places, others are incapable of existence 

 except under typical cave conditions. 



Many of the visitors and a few of the temporary residents occurring 

 just within the mouth of the cave are mere local inhabitants of caves; 

 but the true cave species, those structurally adapted to cave life and 

 living habitually in absolute darkness, are old cave forms which are 

 widely distributed. For example, Platynus, a genus of Carabidae, is 

 represented by 4 species taken occasionally in Indiana caves; Platynus 

 cincticollis Say is taken in Mayfield's and Truett's caves; Platynus 

 tenuicollis Le Conte from Mayfield's, Truett's, Twin, and Donnehue's 

 caves; Platynus punctiformis Say from Mayfield's; a,nd Platynus margin- 

 atus from the Mitchell caves. These species have been taken in different 

 caves and only two of them in more than one. Their occurrence in 

 caves is more or less incidental. They are local cave inhabitants, prob- 

 ably do not breed in caves, and are not at all commonly found there. 



On the other hand, there are 8 American species of the genus Anop- 

 thabnus of blind Carabidae, all but one of which are confined to caves 

 and some of them known from several localities. A. tenuis is known 

 from almost every Indiana cave which has been zoologically explored. 

 This genus is also found in Europe, where there are about 50 species 

 living principally in caves, and where a very closely related species of 

 this genus lives in caves exclusively. Anopthalmus is an old genus 

 widely distributed and highly adapted to cave life. * 



Seasonal changes in temperature are not very marked within the 

 cave and in the remote parts there is as little change in life. The hiber- 

 nating bats and the salamander larvae appear during the winter and 

 the young of Cambarus hay^toni and Cambarus pellucidus testii are 

 observed toward spring, but all other forms of life seem to occur in 

 about uniform numbers the year round and those which breed in the 

 innermost parts of the cave breed when conditions of food are favorable, 

 regardless of the season. However, where there is any marked seasonal 

 change in the temperature of the cave the activity of all cave animals 

 is profoundly affected. From the mouth to "21," and to some extent 

 to the mound, the temperature varies with the season and with the lower 

 temperature of winter the decrease in abundance and activity of cave 



*The genus Anopthalmus has been discarded in Europe, since every intermediate 

 stage between the eyed Trechns and eyeless Anopthalmus has been found. Anop- 

 thalmus is, then, considered a subgenus of Trechus, from which it differs principally 

 in the lack of eyes. 



