46 W. A. LAMBORN. 



Lines for future research. 



An important point for future investigation will be as to the varieties of trees on 

 which the flies settle for a lengthy rest, for hitherto in the Monkey Bay district I have 

 found three only, the baobab, tamarind, and a tree much like our English plane. 

 The baobab, which is especially favoured, affords comparatively dark well-shaded 

 hollows in which the fly can rest comfortably and more securely than in more exposed 

 situations. The general scheme of colour of the fly approximates so closely to that 

 of the bark of these trees as to make it difficult to detect the sitting insects, a fact 

 probably of material importance, seeing that the replete and gravid flies are quite 

 unable to run with the vigour they exhibit under normal conditions, and fly slowly 

 and heavily and by short stages only. On the other hand, though the coloration 

 of the fly does harmonise exceedingly well with that of the tree, it is by no means 

 easy to distinguish the insects on various other trees which, so far as I have yet 

 ascertained, are not regularly favoured. No trees exhibit commonly the recesses 

 usual in the case of the baobab, and the fly must be cooler and more sheltered from 

 the breeze than it would be on the small trees and bushes. 



It is obvious that any attempt to control the fly by systematic capture would be 

 more likely to meet with success if the flies were taken ofT the trees, but at the hours 

 most favourable for such work it is so exceedingly hot that I very much doubt 

 whether natives could ever be persuaded to carry on such work systematically and 

 thoroughly. The ground is unpleasantly hot even to the European's foot protected 

 by heavy boots, so that it is not infrequent to see natives jumping from tuft to tuft 

 of dead grass in the hope of obtaining relief. It has been a matter of difficulty to get 

 carried out even the small amount of such work that I have found necessary. 



I am now about to test the value of bird-lime traps on these trees. 



The Breeding Season. 



Judging by the number of pupae now obtained (October 1915) from captive flies, 

 the breeding season for G. morsitans is in full swing, just as the rains are about due, 

 and there is a marked shortening of the pupal period, which now averages about 

 21 days only, my figures being based on data obtained from 30 bred pupae. It seems 

 that much earlier in the dry season the pupal stage may last certainly as long as ten 

 weeks, hence, as I have previously pointed out, the discrepancy in figures which 

 various workers have given. 



This variability in the rate of development obtains also in the case of Mutilla 

 glossinae, Ewpelminus tarsatus, and the Stomatoceras, and doubtless enables the race 

 to tide over the trying period of the dry season when the conditions of life must 

 threaten the existence of the imagos. 



Glossina morsitans and Large Game. 



In the British Medical Journal of 25th September 1915 appeared a paragraph 

 stating that a large area of territory in Nyasaland has been thrown open for free 

 shooting and that a thorough endeavour is to be made to clear this of tsetse-flies by 

 driving out or killing off the game. The territory referred to, a portion of which I 

 examined last year, is situated in the Marimba district and is said to be richer in game 

 than any other part of the Protectorate. 



