BLACK TERMITE OF CEYLON. 419 



Sooty moulds — Meliola, Capnodium, &c. — were tried, but 

 though these were eaten to a slight extent, the termites 

 preferred to wander away in search of other food rather than 

 consume the " sooty mould " placed on the table near the nest. 

 Ultimately it was found that they were especially fond of a 

 yellow-brown alga {Chroolepis sp.) which clothes the trunks 

 of trees ; and as that occurred on several trees whose bark was 

 broken into readily detachable scales it was possible to collect 

 a sufficient supply. Scales of bark bearing the alga were laid 

 on the table near the nest, and sometimes in the daytime, but 

 generally during the night, the insects removed every particle 

 of alga from the bark. It was observed that the workers 

 carried balls of alga into the nest up to those who were employed 

 in the construction of the comb, and the latter, as also the 

 soldiers, nibbled pieces off. 



Next to the pot on which the nest was built there stood 

 another similar pot, also covered with a bell-glass. When the 

 termites wandered from the nest in search of food, it usually 

 happened that many of them made a mistake when returning 

 and ascended the wrong pot. As the flange of the bell-glass 

 in the second fitted close over the rim of the pot, they were 

 unable to get inside, and for hours together they ran round 

 and round the bell-glass on the horizontal flange. In course 

 of time the flange became covered with black streaks, like 

 the usual track, and it was always possible to observe the 

 formation of the track by wiping off the streaks with a damp 

 cloth for a length of about an inch. When a worker came to 

 the clear space, it halted for an instant, and then began 

 to mark the track again, by ejecting semi-liquid excrement 

 and moving about at the same time so that it lay in short 

 streaks. 



On one occasion a number of termites were observed engaged 

 in this endless round at 10 a.m. ; from time to time individuals 

 wandered off down the pot, and so home, but some of them 

 were still running round at 5 p.m. In order to facilitate their 

 return a bridge of bark, about four inches long, was placed 

 across from one pot to the other, but though some of the 

 soldiers examined it and one of them went halfway across it, 

 none of them made use of it as a way home. This was b\ 



6(8)13 (54) 



