﻿234 LL. LLOYD — NOTES ON GLOSSINA MORSITANS, WESTW., 



mopani), with occasional baobabs {Adansonia digitatd). The ground is scantily 

 clothed with short grass. In places where the swamps are of too long duration 

 for the growth of trees are found stretches of long grass which is fit to burn 

 about September. On the hills, where the woods are less open and composed of 

 various trees, there is denser undergrowth, but it is rarely of an imj >enetrable 

 nature. 



Details of the temperatures experienced and of the humidity of the air are 

 given elsewhere. 



Distribution of Grlossina morsitans. 



G, morsitans is the only species of tsetse-fly that has been met with. It is 

 almost universally distributed in this part of the valley, but in the immediate 

 vicinity of the Luangwa itself it is not often seen.* Dr. Aylmer May informed 

 me that in a long journey up the river he was much struck by this fact. On one 

 occasion my carriers were much bothered by this fly from Nawalia to the 

 Luangwa, but it did not cross the river with us, and on returning next day to the 

 western side I was unable to find a single specimen in several hours search. 

 The only piece of country that is apparently always clear of • fly is a triangular 

 patch extending from the big village Kambwiri to the Luangwa. f I observed 

 nothing in the nature of the vegetation or soil to account for this absence, and 

 game of all kinds is very plentiful in this district. This locality has always been 

 clear of fly so far as we are aware. 



Seasonal variations. 



The fly was very numerous in the valley during the early part of the dry 

 season, but the numbers gradually decreased to the commencement of the rains, 

 when increase was again observed. This corresponds with the numbers of pupae 

 that were obtained in the laboratory. No special decrease was observed at the 

 time of the grass fires. In August the fly was rather numerous on the road from 

 Mpika to the foot of the Mchingas, the first being seen about eight miles from 

 Mpika ; but on returning by this road in March I saw no fly on this section. 

 The weather on both occasions was ideal for fly. 



At the beginning of March I went to the higher ground of the Congo-Zambesi 

 watershed to recommence breeding tsetse in a fresh locality. The site selected is 

 at Ngoa, thirty-two miles N.E, of Mpika, and with an altitude of about 4,000 

 feet. The spot was reached towards the close of the rains and G. morsitans 

 was extremely scanty. The natives of the district affirmed however that as soon 

 as the rains ceased the fly would become numerous. During the first week rain 

 fell nearly every day but after this the weather continued fine. The increase of 

 the insect has been most remarkable and is well shown by the following catches 

 of three expert fly-boys. During the first week the boys brought in 38 females, 

 during the second 71, and during the third 147. 



* Neave, Bull. Ent. Kes. I, p. 306. 

 f Hall, Bull. Ent. Res. I, p. 183, 



