xiii, xiv| @- cart) 
Westwood’s acontias. Occasionally seen flying high, atolmis is 
more common nearer the ground, being much addicted to 
drinking from wet mud on the banks of the Zambesi, or at 
patches of irrigation in the hotel garden. 
4, A. atergatis, Westw. The two types of this are in the 
Hope Collection at Oxford, having been taken by F. Oates 
near the Victoria Falls in January, 1875. There are also two 
specimens in the National collection. Dr. Dixey took four 
specimens near the Falls. 
The other three species exhibited were commoner and fell 
to the nets of Dr. Dixey, Professor Poulton, and the exhibitor. 
Professor E. B. Poutron, F.R.8., exhibited two Diptera, 
which had been observed following the bee, Andrena labialis, 
Kirb., by Mr. A. H. Hamm, assistant in the Hope Depart- 
ment, Oxford University Museum. The specimens have been 
compared with Mr. G. H. Verrall’s collection and identified 
as Chortophila unilineata, Ztt., by Mr. J. HE, Collin, Mr, 
Hamm’s notes were as follows :— 
“During the afternoon of May 27th, 1900, I was sitting 
watching a fairly numerous colony of Andrena labialis, 
nidificating on the sloping side of a small clay pit, near 
Bagley Wood, Oxford. My attention was arrested by the 
surprising behaviour of a fly, which kept following up a 2 bee in 
the most persistent manner. The bee seemed conscious of the 
attention of the fly, and instead of making direct for the 
burrow, it zigzagged about and sometimes alighted on the 
ground, as if endeavouring to get rid of its pursuer; but 
the fly was not to be shaken off; for it followed the bee in 
all its movements, settling on the ground and resuming its 
flight at the same time as the Aculeate. Throughout this 
persistent pursuit the fly kept at a fairly uniform distance 
of about six inches behind the bee. I saw about six of these 
flies altogether, but no single bee was followed by more than 
a single fly. I netted the two flies exhibited by Professor 
Poulton, in one case capturing pursuer and pursued at a 
single sweep.” 
Professor Pounron stated that new and interesting light 
had been thrown on the observation by Col. Yerbury, who 
pointed out that both flies were males. At first sight it 
