BLACK TERMITE OF CEYLON. 405 



the time and duration of the processions made by the inhabitants 

 of a nest kept in his laboratory at Ambalangoda. In general, 

 the procession set out about 6 p.m., or between 4 and 5 on dull 

 days, while the return was completed by about 9 a.m. the 

 following morning. The later time of setting out, as compared 

 with that at Peradeniya, is perhaps what would be expected 

 to occur in the low-country ,where the sun's heat is more intense. 



The insects follow the same track for weeks, or even months, 

 together. To enable them to do that, they mark their course 

 with minute streaks of excrement, applied in the more liquid 

 form as used in the construction of the comb, so that after a 

 few journeys the track becomes a broad black streak down the 

 stem of the tree and along the ground. This is evident on 

 PI. VII. running obliquelj^ do^\'n wards towards the right hand 

 lower corner, while on PI. VI.a two tracks appear running 

 doAvn to the left. Plate IX.a is a photograph of a track, 

 one-sixth natural size, along a whitewashed wall, and PI. IX.B 

 shows the same track, magnified one and a-half times, the 

 individual streaks being visible. Where the track traverses a 

 sandy path, the surface particles of sand are cemented together 

 after a few weeks' travel, and can be lifted up in sheets two or 

 three inches in length ; while the way over rough patches of 

 fine gravel is smoothed by the deposit of pellets of excrement 

 similar to those of which the external hanging mass is built. 

 Escherich is inclined to regard the black streak as in some 

 respect different from excrement, as it differs in consistency and 

 form from the pellets of the external hanging mass. But it has 

 the same microscopic characters as the latter, and is identical 

 with the excrement of which the inner comb is built ; and, as 

 stated above, the insects make use of either form to mark 

 their path according to the character of the ground traversed. 



There is generally a well-defined track do\\-n the tree trunk ; 

 and the insects leave the nest and travel along it in full column 

 without any hesitation. If the track on the ground has been 

 in use for some time, their progress along it is equally steady 

 and uninterrupted. Bugnion observed that under such 

 circumstances the workers travelled at the rate of about one 

 metre per minute. But when no old path exists to guide them, 

 their progress is necessarily slower and less regular. The 



