256 
EASTERN ETHIOPIA 
XX 
these little musical boxes are often the dwelling-places 
of ants. If these strange habitations be tapped on the 
outside, the ants swarm out to fight the disturbers of 
their peace. 
It is possible that' the ants are responsible for the 
formation of these strange wdnd instruments. Schwein- 
furth gives a weird description of a concert in one of 
these acacia groves around Fashoda (now Kodok) where 
'‘the voices of a thousand flutes give out their hollow 
dirge.” 
The thorns of the Acacia fiAiiIosa. 
The umbrella shape of the thorn trees and their 
leaflessness protect them against the' tornadoes which 
occasionally sweep over the Nyika. The most marked 
reduction of leaves is seen in the acacias, for they 
become mere spines, or needles, the fleshy tissue being 
lost, and nothing but the vascular bundles persisting. 
An acacia-grove has been aptly described as a “ thorn- 
orchard.” In extreme instances respiration is effected 
by the green succulent stems of plants. In the big 
leaves of the aloe and sansevieria there are few stomata. 
