February, '17] 



McCOLLOCH: UNDERGROUND INSECTS 



185 



is the normal time of emergence in the field. Grasshopper eggs hatched 

 in the cave at the same time that eggs were hatching in the field. The 

 larvae of Eleodes opaca and E. tricostata pupated in the spring and the 

 adults emerged at the same time that fresh adults were being found 

 outside. 



A study of the temperature records of the cave is very interesting. 

 From October 11 to November 8, the average mean temperature was 

 about 63° with a daily range of from one to two degrees. From No- 

 vember 8 to February 11, the temperature gradually fell from 62° to 37°, 

 a drop of 25° in 95 days, or an average of about one-fourth of a degree 

 per day. From February 11 to March 6, the temperature remained 

 practically constant at from 37° to 38°. On the latter date it gradually 

 began to rise. From January 17 to March 18, a period of 61 days, the 

 temperature remained constant at from 37° to 40°. The daily fluctua- 

 tion of temperature within the cave, with the exception of one day, did 

 not exceed two degrees. There were 62 days when it remained con- 

 stant, 101 days when there was a one degree fluctuation and 26 days 

 when the range was two degrees. The average daily range of tempera- 

 ture outside for this same period was 21.5°, with extremes of 3 and 50°. 

 On January 11 to 13, the outside temperature fell from 53° to —16°, 

 a drop of 69°, while there was a drop of only 3° in the cave. The 

 average mean temperature of the cave and the outside, together with 

 the range of temperature in the cave, is shown in the accompanying 

 chart (Fig. 8). 



This temporary cave proved so successful that in the summer of 

 1916 a permanent cement cave was constructed. The floor of this 



