332 
EASTERN ETHIOPIA 
XXVII 
convert straw and wood into this red material. Hayes 
is strongly of opinion that much of the mud carried 
down by the Nile is due to the activity of termites 
in the western borderland of Abyssinia. 
Drummond, in an interesting essay on termites, 
gives an account of the ravages committed by these 
insects on the trees of the great plateau between Lakes 
Nyasa and Tanganyika ; he also draws attention to the 
enormous amount of earth which is removed by the 
termites from the deeper layers of the soil and brought 
to the surface for the construction of their nests and for 
covering the bark of trees. During the dry season 
this work goes on incessantly, and much of it becomes 
distributed by the wind as dust, and serves as a 
top-dressing to the vegetation around. In the rainy 
season, which lasts intermittently for weeks, the loose 
soil is washed away in quantities, and some of the 
termitaria, though they have great resisting powers, are 
not invulnerable, and ultimately succumb to denuding 
aoents such as mud and rain. 
This is an interesting theory and worth consideration, 
especially when taken in conjunction with Hayes’ 
observation, for he explained to me that the red earth 
which is such a conspicuous feature of the mud brought 
down l)y the Nile, ordinarily described as coming from 
the Abyssinian Highlands, is not to be seen apart from 
the districts in which termites abound. 
Tei*mites ai'e blind, but when disturbed they express 
their alarm by hissing ; it is well established that they 
have means of communication by sound. The exact 
mode in which the sound is produced remains unknown. 
Although termites are blind they can inflict sharp bites 
with their mandibles. 
liTthe winged state the termites are much altered in 
shape and form. They have a pair of eyes, and four 
wings, but these differ from the wings of most insects, 
for they are only used for a single flight, and are then 
shed by detachment at a suture which exists across the 
