48 FAUNA OF MAYFIELD'S CAVE. 



or to their becoming partially warmed after reaching the laboratory. 

 When placed in a dark room where the temperature ranged from 6 to 

 14 C. they became less active again, but seemed to become hardly as 

 dormant as before. It seems most likely that the activity of this moth 

 is directly influenced by temperature. However, the following peculiarity 

 in its behavior was noted: 



September 24, 1904, when many of these moths had already entered 

 the cave, the temperature outside was 20.6 C., the average for the 

 preceding week had been 18.8 C., while the minimum had been 10.6 C. 

 The temperature at ''6" was 11.9 C. October 15, when all the moths 

 had entered the cave, the temperature outside was 12 C. ; for the pre- 

 ceding week it had been 15.5 C., while the minimum had been 5 C. 

 The temperature at "6" was 11.6 C. April 8, 1905, when nearly all 

 the moths had left the cave, the temperature outside was 5.3 C., the 

 week's average had been 12.9 C., while a minimum of C. had been 

 reached three times. The temperature at "6" was 7.4 C. April 29, 

 when all had disappeared, the temperature outside was 16.4 C., for 

 the preceding week had been 14.5 C., and a minimum of 5 C. was 

 reached. The temperature at "6" was 8.3 C. From these figures it 

 will be seen that Scoliopteryx libatrix leaves the cave while the temper- 

 ature where it spent the winter is 4 C. lower than when it entered the 

 cave, while the average outdoor temperature was 8 C. lower than when 

 it went into winter quarters. The temperature just within the cave is 

 rapidly rising at the time the moths leave, but does not get as high as 

 that when they entered the cave until midsummer. 



These moths seldom change their positions in the cave after becoming 

 settled in the fall until about time for their departure in the spring. 

 There are indications that some of them shift their positions somewhat 

 soon after arriving and just before leaving, but I doubt if at other times 

 they move at all unless disturbed. 



In the cave this species shows an almost perfect orientation with 

 regard to the light. Nearly every individual takes a position with the 

 axis of its body in the direction of the rays of light and with its head 

 from the source of light. There are some exceptions to this rule, but 

 it is true in 80 or 90 per cent of the cases. Those individuals which are 

 on the wall do not seem to head from the direction of light so much as 

 those on the roof, but this seems accounted for in the cases of some of 

 them which are subjected to reflected light from different directions. 

 Those under overhanging shelves are sometimes subjected to light which 

 has become so diffused that there is no one direction from which it 

 seems especially to come, and very naturally these individuals are headed 

 without regard to the direction of the mouth of the cave. Just past 



