72 LL- LLOYD. 



Destruction of pupae by bush fires. 



The pupae collected were kept in wide glass tubes closed at the top by a double 

 layer of muslin to prevent the escape of small parasites. They were protected fi'om 

 the heat as far as possible during the travelhng by being placed in boxes wrapped in 

 mushn, and these again in a stout wooden case lined with several layers of blotting 

 paper. A considerable number in each series died, but the mortality was much 

 higher in those from the areas over which the fires had passed at Ngoa. 



From these jSgures it is seen that in the burnt areas about 12 per cent, were dead at 

 the time they were collected, and from some cause not present in the unburnt areas. 

 This cause was almost certainly the fire. In area (4), which included old gardens, 

 170 pupae were taken from under the remains of the fences. The fences had been 

 largely burnt and the pupae were taken under the small stretches that remained, 

 being in many cases dug up from amongst the ash. It is obvious that any pupae in 

 such positions would be killed by the fire. No accurate estimate of the proportion 

 that are destroyed by this means can be gathered from these figures, since the 

 collections were made too long after the burning. A series collected immediately 

 after a bush fire would probably give interesting results. 



Breeding Places. 



Enough has been said to show that the flies breed most freely in spots to which the 

 game is most attracted. Up to the present 700 breeding places have been examined, 

 and all agree in the one respect, that over or very close to each is some relatively dark 

 hiding place for the flies. These places have been found in all types of 

 country wherever they have been looked for in fly areas, with the exception of a 

 stretch of thin mopani forest close to Nawalia. A day was spent in searching this 

 piece of country in the height of the breeding season. Fly was fairly numerous and 

 game paths ran in every direction, but only two empty and old cases were found. 

 No explanation can be given of this, as pupae were taken very freely in a similar 

 piece of mopani bush near Chutika. An area of long grass country near Chutika 

 yielded few pupae, but on a closely similar stretch near Ngoa many were found. 



Two or three of the positions will be discussed, as they differ from any that have 

 previously been described, and they show that it is improbable that any special 

 odour, such as that of humus, attracts the pregnant flies. 



(1). Under overhanging rocks in a vlei near the Lukanga River, Kashitu, ten 

 empty cases were taken. The hollows under the rocks were deep and dark, without 

 vegetation. The spot was an occasional haunt of reedbuck. 



(2). Chutika, in the thin mopani forest. A little hollow in the ground about two 

 feet long, one broad and one deep, forming the commencement of a flood stream bed. 

 The bottom was of pebbles, and the sides were of alluvial clay and much creviced. 



