TACHINOIDES IN BORNU PROVINCE, NORTHERN NIGERIA. 121 
very numerous, attacking the men vigorously. They also bit me freely through 
white canvas leggings and khaki breeches. 
Walking along the river-bed, I noticed that the flies were numerous at certain 
spots, while at others, none were seen. Wherever they were numerous, there was 
always a pool of water near by, and I found the flies to be sheltering in the low 
spreading straight-stemmed bushes, shown in the photograph (fig. 2), close to the 
Fig. 2.—River-bed near Pyem ; tsetse-flies were observed to shelter specially in the bushes 
shown on either side of the fore-ground. 
pools. On shaking these bushes, several more flies were seen, though we failed 
to observe a single fly actually at rest upon them. After biting the men, the flies 
disappeared, and it seemed impossible to discover their actual place of rest, but 
it was obvious that they retired into these bushes, for on shaking them the flies 
reappeared at once. We very carefully searched the sand and soft mud in the 
vicinity of the bushes for pupae, but failed to find any. The small trees and 
thorny bushes around did not appear to harbour any flies, for when shaken no 
increase in the number of tsetses was observed. 
I had my table set down on the edge of a clear space some 300 or 400 yards 
from the river-bed, and thither the flies followed me, and were so troublesome 
