"tsetse" fly.

It still wanted some minutes of sunset, and the horses were permitted to
browse freely, but Von Bloom observed that they were every moment
getting more excited--now striking their hoofs upon the turf,--now
running a length or two--and at intervals snorting angrily. At the
distance they were off--a quarter of a mile or so--Von Bloom could see
nothing of what was disturbing them; but their odd behaviour at length
induced him to walk up to where they were. Hans and Hendrik went along
with him.

When they arrived near the spot, they were astonished at what they then
beheld. Each horse seemed to be encompassed by a swarm of bees!

They saw, however, they were not bees, but insects somewhat smaller, of
a brown colour, resembling gad-flies, and exceedingly active in their
flight. Thousands of them hovered above each horse, and hundreds could
be seen lighting upon the heads, necks, bodies, and legs of the
animals,--in fact, all over them. They were evidently either biting or
stinging them. No wonder the poor brutes were annoyed.

Von Bloom suggested that they should drive the horses farther out into
the plain, where these flies did not seem to haunt. He was only
concerned about the annoyance which the horses received from them.
Hendrik also pitied their sufferings; but Hans, alone of all the three,
guessed at the truth. He had read of a fatal insect that frequented some
districts in the interior of South Africa, and the first sight of these
flies aroused his suspicions that it might be they.

He communicated his thoughts to the others, who at once shared his
alarm.

"Call Swartboy hither!" said Von Bloom.

The Bushman was called, and soon made his appearance, coming up from the
spring. He had for the last hour been engaged in unpacking the wagon,
and had taken no notice of the horses or the interest they were
exciting.

As soon, however, as he got near, and saw the winged swarm whirring
around the horses, his small eyes opened to their widest extent, his
thick lips fell, and his whole face yielded itself to an expression of
amazement and alarm.

"What is it, Swart?" inquired his master.

"Mein baas! mein baas! der duyvel um da--dar skellum is da 'tsetse!'"

"And what if it be the tsetse?"

"Mein Gott!--all dead--dead--ebery horse!"

Swartboy then proceeded to explain, with a loud and continuous
"clicking," that the fly which they saw was fatal in its bite, that the
horses would surely die--soon