DR. EMIL HOLUB. 191 
THE MIGRATION OF HIRUNDO RUSTICA TO 
SOUTH AFRICA. 
BY DR. EMIL HOLUB, VIENNA. 
Iris commmonly known that the European Swallow winters 
in Northern Africa, but it may be known to few that by far 
the largest number of this species migrate to the southern 
portions of the Dark Continent. 
Every year, from October to March, through the eleven 
years of my sojourn in South Africa, and in the very midst 
of the southern summer, I have seen these Swallows hunting 
up and down the endless plains, destroying vast numbers of 
the myriads of southern insects, and uniting every evening 
into swarms of thousands, in some spots of hundreds of 
thousands, to seek their resting-places for the night. 
In the following I will refer to one of those sleeping-places, 
asking the kind reader to accompany me to that lonely spot, 
visited by me on a day in November twenty-five years ago. 
We are in the midst of an endless plain. Toward the east, 
hardly perceptible by its treeless banks, the Harts Spruit * 
takes its southwesterly course to the Vaal River, a right-hand 
tributary of the Kai Gariep or Orange River, the latter in its 
lower course being a natural boundary line of Cape Colony 
toward the north, The grassy cover of the plain is about 
* A spruit is a river flowing after heavy rainfalls for a few days or 
weeks only; most of the year such a river is dry, with the exception of 
some of the deepest places in its bed, which contain water for a few 
months. 
