[96 fetch : tup: i'TM;i 



Lering the temperatures near the mouth of the chimney 

 ad that the daily variation is considerably less than the 

 variation of the external temperature. The internal tem- 

 perature never reaches the external shade maximum, and its 

 minimum is about 1<> F. above the external minimum. A 

 sudden fall of temperature in the afternoon due to heavy rain 

 causes no corresponding variation in the nest. An external 

 daily variation of about 20 F. is accompanied by an internal 

 variation of only 5-8° F. The internal temperature only falls 

 about 2° F. during the night, excepl when the previous after- 

 noon is cloudy, when it may fall 4 F. The results at tin- 

 depth of 80 centimetres show only a daily variation of 

 2-4° F. The minimum is about 14° F. above the external 

 minimum, and is sometimes not reached till mid-day if the 

 morning is dull. The maximum is several degrees below the 

 external maximum, and is not reached till about sunset or 

 later. This remarkable lag of the internal maximum and 

 minimum seems to indicate a gain and loss of heat by direct 

 radial ion only. 



The maxima and minima in the last two columns are not 

 Strictly comparable with the other readings as they were 

 nol taken in the immediate neighbourhood of the nest : they 

 are included merely to give a general idea of the daily range 

 of temperature at Peradeniya during the nottesl and driest 

 niont h of the j ear. 



An interesting point with regard to the chimneys was raised 

 by observations Oil Constructions made by true ants. One 



large species, Myrmecaria brunnea, Saunders, brings up from 



it- ne i underground grains of sand and particles of earth 



through a small hole about a centimetre in diameter: it 



generally observed On footpaths. These particles are at 



tii-t arranged on one Bide of the bole in a crescentic mound 

 aboul 3 centimetres high which curves round and slopes 

 away to nothing on either side of the hole, the distance be- 

 tween the vanishing horns of the orescent being about 12 



htimeti.- The ante run up the slope from the hole with 



