120 ARKIV FÖR ZOOLOGI. BAND 12. N:0 15. 



situated above the ground-level, to stav in the cooler subter- 

 ranean parts during the hottest hours of the day. This is the 

 case with the termites of the nests of Euiermes Tyriei Mjöb., 

 Hamitermes laurensis Mjöb. and Hamitermes scopulus Mjöb. 

 In most nests not one single termite can be found in the 

 upper parts from about 9 a. m. to about 4 p. m. Låter in 

 the day and during the cooler night-hours the nests are 

 crowded with soldiers and workers. This is a fact I have 

 been able to prove by opening at least a couple of hundred 

 nests during the day at various hours. Låter in the evening, 

 when the sun has already set and the temperature sinks 

 considerably the termites go down again into the under- 

 ground parts, where higher temperature prevails in conse- 

 quence of the immense heat having been absorbed during 

 the hot hours of the day by the soil, which retains the heat 

 better than the barder upper parts of the nest. 



During my caravan expedition through Cape York Penin- 

 sula from Laura to Coleman River (Aug. — Okt.) I obser- 

 ved the termites in the small nests of Hamitermes lau- 

 rensis Mjöb. As soon as the sun showed the first signs of 

 rising, we made a start. Every morning between 4 — 5 a. m. 

 I cut off the small nest with an axe, this making a cross- 

 section only some centimeters above the ground. The few 

 termites which were to be found in the nests were all 

 congregated, slowly crawling in one mäss, at the eastern wall, 

 apparently trying to warm themselves a t the first rays of 

 the sun. Not a single termite could be discovered in the 

 western parts of the nest. Apparently the termites are very 

 sensitive to temperature changes. 



In the narrow flattened nests of Hamitermes meridio- 

 nalis Frogg, the interiör parts are not so hot as in the 

 conical or flattened nests. We also find that not a few 

 termites move about in the lower and median parts of these 

 nests. For these reasons I have come to the conclusion, 

 that the flattened form of the »magnetic» nests is an adap- 

 tation to the hot sun, their peculiar way of facing the 

 rising and setting sun an adaptation to the strong north 

 wind prevailing during certain seasons. 



In the nests of Hamitermes meriodionalis Frogg., Hami- 

 termes laurensis Mjöb. and Eutermes Tyriei Mjöb. I made 

 the very interesting discovery that certain parts of the nests 



