BIOLOGY OF THE SHAWNEE CAVE SPIDERS. 315 



end in clear weather, one half the time in the dark end during 

 cloudy weather, and usually in the lii;ht end when dark. The 

 -piderl: remained in the dark end one half the time 



in clear \\eather. one third the time in the dark end during cloudy 

 her and mo-t of the time in the li^ht end when dark. 



All ei^ht eyes in the .1/VM\ \\ere present and presumabK well 

 de\elo])ed. The anterior middle OIH-- v nerallx a little 



^mailer than the other- an 1 , a-nmally an eye \\a- found anioii- 

 tin- other- which wa- about one half -i/e. In all the-e experiments 

 forty .!/<.',." \\ere n-ed. 



The following table gives the re-ult- of the liijit experiments 

 tor / >!yf}hnn!'^. <>uthe left i- entered the number of the 



specimen, the localil .'. he t her mature or immature 



and the four \MI. -land- for anterior middl* 



I'M I tor |io-terior middl' \H for anterior -ide itnl 



I'^l for po-ti rior -ide < All mea-uremeiit - \\etv made \\ith 



a mil lometer -lide in-ide the i wo inch ocular \\ith i u o third- or 



lo\\ nbjet li\e. \\hellthee\e-\v 1 \ 1 1 i -< elllible t he olie- 



iin li o, ul.ir \\as -iib-lituied for the i \\o-inch. A- a unit of meas- 

 urement tor the in- lifty-tiflh of a millimeter O.OlB mm 



I. Phe f 1 nal |.at 'mil are mil> approxi- 



mate. The '- are U-ed uhell tile e\"- are joined together, if 

 sej.arate einplo\ed. 1* stand- tor pigment Speck. The 



under i- -eli-e\planat 



The thirl\ example- included in tin- table \\ i : I, not 



on a photoiropic ba-i-, but nt the \ariou- localilie-. 



the iteration o| "the :n 1 --lorat ion. It another 



table \\ere made Iroiu th.- -]>eciinen- not included in thi- one, t he 

 re-uli- \\oiild be -imil.ir If .' c. .rn-ciii .11 could be made for 

 rloudx \\eatln r and for the ti: ii)tied in ^oin^ inlo the dark, 



the total i .t. of .).) for tho-e in the- dark column would be 



ion-id -rabl\ larger than the total per lent, ol 51 lor tho-e in the 



li.uht column. In all these experiments 225 specimens have been 



1 and I am po-iii\elv (crtain that the result- ..- .i\en in the 

 tabl are correct. 



Summari/in- the following table and other data not included 

 therein \\>- have the t'ollou iiv.; statements: 



T\\ent\--ix per cent of all the indixidual- examined had no 



