NOTES ON THE TSE-TSE FLY

Connection between buffaloes and tse-tse flies—Sir Alfred Sharpe's views—Buffaloes and tse-tse flies both once abundant in the valley of the Limpopo and many other districts south of the Zambesi, in which both have now become extinct—Permanence of all kinds of game other than buffaloes in districts from which the tse-tse fly has disappeared—Experience of Mr. Percy Reid—Sudden increase of tse-tse flies between Leshuma and Kazungula during 1888—Disappearance of the tse-tse fly from the country to the north of lake N'gami after the extermination of the buffalo—History of the country between the Gwai and Daka rivers—And of the country between the Chobi and the Zambesi—Climatic and other conditions necessary to the existence of the tse-tse fly—Never found at a high altitude above the sea—Nor on open plains or in large reed beds—"Fly" areas usually but not always well defined—Tse-tse flies most numerous in hot weather—Bite of the tse-tse fly fatal to all domestic animals, except native goats and perhaps pigs—Donkeys more resistant to tse-tse fly poison than horses or cattle—Tse-tse flies active on warm nights—Effect of tse-tse fly bites on human beings.

As it is impossible for any one who had much experience with buffaloes in the interior of South Africa in the days when these animals were excessively plentiful not to have a very lively remembrance also of the tse-tse flies by which they were almost invariably accompanied, I think a few words concerning these insects will not be out of place. My remarks must, however, be understood to apply not to all tse-tse flies—for there are several distinct species of the genus inhabiting different parts of Africa—but to Glossina morsitans alone, which, so far as I am aware, is the only species of tse-tse fly as yet known to occur in Africa to the south of the Zambesi river.

In the countries farther north, men of great experience have expressed the opinion that there is no connection between tse-tse flies and buffaloes or any other kind of wild animals. Writing on this subject, Sir Alfred Sharpe has recently stated, in the course of an article published in the Field newspaper for November 2, 1907:

So far as Africa north of the Zambesi is concerned (i.e. British Central Africa, North-Eastern Rhodesia, Portuguese East Africa, the south-west portion of German East Africa, and the south-east corner of the Congo State), I am able to speak with some experience, having spent twenty years in those regions. The results of the last few years' careful observation have led me to a decided opinion that the existence of tse-tse is not dependent on wild game of any description. Tse-tse (mostly Glossina morsitans in British Central Africa), when it has the opportunity, sucks the blood of all such animals as it can get at in tracts of country in which it exists, but I think that blood is an exceptional diet (as in the case of the mosquito).

The great experience which Sir Alfred Sharpe has enjoyed in British Central Africa—which territory he has so ably administered for many years—entitles any views he may express on any subject concerning that country to the very greatest respect; but it must, nevertheless, be said that the conclusions he has arrived at concerning the requirements and life-history of the tse-tse fly (of the species Glossina morsitans), in the countries lying to the north of the Zambesi river, in which his observations have been made, are diametrically opposed to the teachings of history throughout the whole of Africa to the south of the Zambesi, where not only would it seem that these insects live entirely upon mammalian blood, but that they have become so highly specialised that they can only maintain their vitality on the blood of buffaloes; for it can be shown that wherever tse-tse flies were first encountered by the earliest European travellers in South Africa, there also buffaloes were either constantly present or visited such districts during certain months of every year; and that as soon as the buffaloes were either exterminated or driven out of any such territories, a remarkable diminution in the numbers of the tse-tse flies was at once observed; whilst in a very few years after the complete extinction of the buffaloes these insects entirely ceased to exist, even though other kinds of game remained in the country for years afterwards. A few facts bearing on this subject, which, being historical, can neither be questioned nor, I think, explained away as coincidences, are well worth enumerating.

In 1845 Mr. William Cotton Oswell—the well-known traveller and hunter—encountered tse-tse fly on the Maghaliquain river, a tributary of the Limpopo running through the Northern Transvaal, and it is an historical fact that at that time the whole of the Northern Transvaal lying between the Waterberg and Zoutpansberg ranges and the Limpopo, as well as a large area of country lying to the north of that river, was the haunt of great herds of buffaloes, and that the banks of every river draining this large territory, as well as many tracts of forest lying between these rivers, were at the same time infested with tse-tse flies.

In 1871 the well-known traveller Mr. Thomas Baines, as he has recorded in his book The Gold Regions of South-East Africa, still found the tse-tse fly numerous on the Maghaliquain river, as well as in the neighbourhood of the Macloutsie and Shashi rivers, and in many other places throughout the valley of the Limpopo.

In the following year, 1872, I visited Matabeleland for the first time, and it is within my own knowledge that at that time buffaloes were still plentiful in many parts of the valley of the central Limpopo.

About this time the natives of every tribe in South Africa were acquiring guns and ammunition in immense quantities in payment for work in the recently discovered diamond mines. The first result of the acquisition of firearms by the natives of the Northern Transvaal and the countries farther north was the destruction of all the buffaloes throughout the valley of the Limpopo to the west of the Tuli river, and it is a well-known fact that in a very few years after the disappearance of the buffaloes from this large area of country the tse-tse fly had also absolutely ceased to exist.

Yet for years after the disappearance of both buffaloes and tse-tse flies from the valley of the central Limpopo and its tributaries, other game, such as zebras, koodoos, wildebeests, waterbucks, impalas, and bushbucks, continued to exist in considerable numbers. I myself found all these animals still fairly numerous in 1886 along the Maghaliquain river, as well as on the Limpopo itself and along the lower course of the Macloutsie and Shashi rivers, and it seems to me that there can be no doubt that after the buffaloes had been exterminated the tse-tse flies gradually died out, because they could not maintain themselves on the blood of other kinds of game.

Again, it is an historical fact that when gold was first discovered in the Lydenburg district of the Transvaal, in the early 'seventies of the last century, the whole of the low-lying belt of country near Delagoa Bay was infested with tse-tse fly, and that buffaloes were also very plentiful in the same district.

Very heavy losses in cattle were the result of the first attempts to carry goods by ox waggon from LourenÇo Marquez to the Transvaal gold-fields. Ox-waggon transport was then abandoned and a service of donkey waggons established by, I think, a Mr. Abbot. Donkeys, however, though far more resistant to tse-tse fly poison than cattle, were found to soon grow weak from, and sooner or later to succumb to, its effects. Gradually, however, the buffaloes got killed off throughout the low country lying between the Lebombo range and the sea, and the tse-tse fly then gradually diminished in numbers, until, though many other kinds of game remained in the country, the waggon road leading from Barberton to Delagoa Bay at last became quite free from these insects.

It is a well-known fact, too, that up to the year 1878 buffaloes were plentiful on the Botletlie river to the south of Lake N'gami in the neighbourhood of the Tamalakan, where Livingstone and Oswell lost so many of their oxen from tse-tse fly bites in 1853.

Up to the year 1878, too, there were still two "fly"-infested tracts of forest to the west of the Botletlie, through which the waggon road to Lake N'gami from Bamangwato passed. These "fly" belts were always crossed during the coldest hours of the night by traders and hunters travelling to or from Lake N'gami with cattle and horses. During the year 1878 a number of emigrant Boer families, on their way from the Transvaal to Portuguese West Africa, spent several months camped along the Botletlie river. The men belonging to these families were all hunters, and they killed a great many buffaloes, and drove those they did not kill far up the Tamalakan. After 1878 no buffalo was ever seen again on the Botletlie river, and soon after the disappearance of the buffaloes the tse-tse flies, which had up to that time constantly infested two belts of forest near the western bank of the river, ceased to exist. There are neither tse-tse flies nor buffaloes along the Botletlie river to-day, though several species of antelopes as well as zebras were a few years ago, and are probably still, existent there.

Again, in the early 'seventies of the last century there were two "fly" belts lying across the road from Bamangwato to the Zambesi, the first a tract of forested country some twelve miles broad, situated to the south of Daka, and the second occupying a lesser extent of ground of similar character between Pandamatenka and the Zambesi. At the same date, all along the southern bank of the Zambesi and Chobi rivers to the westward of the Victoria Falls, tse-tse flies were present in such numbers that it was no exaggeration to speak of them as swarming, or as resembling a swarm of bees, whilst prodigious numbers of buffaloes were likewise to be found all the year round in the same locality. The buffaloes seldom went more than a mile or so away from the river, and it was my experience that where the buffaloes did not penetrate, the country was entirely free from "fly." Both the one and the other were confined in this part of the country to the near vicinity of the river, where, however, both literally swarmed. In the "fly" belts aforementioned, crossed by the waggon road to the Zambesi, buffaloes were only present during the wet season and the early part of the dry season, retiring eastwards as the vleys dried up. In these "fly" belts, however, tse-tse were not nearly so numerous as along the Zambesi and Chobi, where the buffaloes were present all the year round. Constant persecution from about 1876 onwards, chiefly by natives armed with guns, soon stopped the buffaloes from coming into the "fly" belts crossed by the waggon road to the Zambesi, and a few years later these animals had also entirely ceased to visit the southern bank of the Zambesi between the Victoria Falls and the mouth of the Chobi. After the buffaloes ceased to visit the tracts of forests infested by "fly" on the road to the Zambesi, these insects very soon entirely died out, though other kinds of game still remained in both those districts. Along the southern bank of the Zambesi to the west of the Victoria Falls the tse-tse flies began to diminish in numbers as soon as the buffaloes ceased to frequent this part of the country. It took some years certainly before the tse-tse had quite died out in this strip of country, but for many years past now neither buffaloes nor tse-tse flies have been seen in that district, where, however, game of various kinds other than buffaloes continued to exist long after the tse-tse flies had completely disappeared.

When exactly the buffaloes ceased to visit the neighbourhood of the Victoria Falls and the two tracts of country that were once known as "fly" belts on the road to the Zambesi, and how long it was after the disappearance of these animals that the tse-tse flies entirely died out in these same districts, I have been unable to ascertain. In 1874 I found both buffaloes and tse-tse flies in all these districts, and in 1877, on my second visit to the Zambesi, although I did not see any buffaloes or their fresh tracks in the two "fly" belts crossed by the waggon road, tse-tse flies still haunted both these localities, as I myself observed, and as has also been recorded by the late Dr. B. F. Bradshaw. I believe, however, that these insects were at that time rapidly diminishing in numbers in both those districts, owing to the fact that the buffaloes had almost ceased to come amongst them. In October 1877 I accompanied Dr. Bradshaw from Kazungula—where the Chobi joins the Zambesi—to the Victoria Falls. We walked the whole way along the bank of the Zambesi and found tse-tse fly very numerous everywhere, especially near the Falls. At this time buffaloes were already becoming scarce to the eastward of the junction of the Chobi with the Zambesi, most of them having already moved westwards up the course of the former river.

Eleven years later, in 1888, I travelled over the old waggon road to the Zambesi for the last time. Both buffaloes and tse-tse flies had then long since disappeared from the stretch of country to the south of Daka as well as from the "fly" belt to the north of Pandamatenka, whilst they were also entirely absent from the southern bank of the Zambesi near the Victoria Falls. There was still, however, a certain amount of game—zebras and several species of antelopes—left in all these districts.

In December 1888 I took two horses to the Falls, and rode one of them all along the narrow strip of open ground between the Rain Forest and the edge of the chasm into which the river falls. It seemed strange not to see a single "fly" in this district, where these death-dealing insects had literally swarmed only eleven years earlier.

Farther westwards, however, tse-tse flies continued to haunt the southern bank of the lower Chobi river in great numbers long after the buffaloes had ceased to live there constantly, though these animals still visited the district during the rainy seasons. At such times they probably grazed down the river in great numbers to within a few miles of its junction with the Zambesi.

A letter I have lately received from my old friend Mr. Percy Reid, who has made many hunting trips to the Chobi and Zambesi rivers, the last two of which were undertaken, the one the year before and the other three years after the epidemic of rinderpest had killed off all the buffaloes on the lower course of the Chobi river, throws a great deal of light on the disputed question as to whether or no there is or has ever been any connection between the buffalo and the tse-tse fly in South Africa.

In the course of his letter Mr. Reid says:

I was at Kazungula (the junction of the Chobi and Zambesi rivers) in 1885, 1888, 1895, and 1899. In 1885 I did not take my oxen beyond Pandamatenka, as it was not considered safe to take them to Kazungula; but even in that year I saw no "fly" between Leshuma[9] and the junction of the rivers, though I remember that a few were said to still exist there at that time. There were no buffalo there then, and the fact that the "fly" still lingered in this district was put down, though I do not know with how much truth, to the great number of baboons which, as you will remember, always frequented the bush near Kazungula.

[9] Leshuma is ten miles south of Kazungula.

In 1888 and subsequent years I sent oxen and horses backwards and forwards from the river to Leshuma at all hours of the day, and never lost any from "fly" bites.

In 1895 there were plenty of both fly and buffalo up the Majili,[10] and swarms of fly up the Chobi, but I did not go very far, and saw no buffalo there.

[10] A river running into the Zambesi from the north, not far above its junction with the Chobi.

In 1899, only three years after the rinderpest had swept off all the buffaloes, I went along the north bank of the Chobi right past Linyanti, and, crossing above the swamps, came back along the south bank. There was not a fly to be seen where, only four years before, I had counted thirty or forty on a native's back at one time, and we had actually to light fires and sit in the smoke to protect ourselves from them. On the whole trip we saw no buffalo, and only got fairly old spoor of one very small lot on the north bank. I certainly always understood that in a very few years after the buffalo disappeared from any district the "fly" followed suit. All the old hunters up on the Zambesi were agreed on that point, and I recollect George Westbeech[11] saying the same thing.

This letter conclusively proves that although tse-tse flies continued to swarm along the southern bank of the Chobi to within a short distance above Kazungula for some years after the buffaloes had ceased to live all the year round in this district (as they used to do up to the early 'eighties of the last century), and only spent the rainy season there, these insects absolutely disappeared within three years after the final destruction of the buffaloes by rinderpest in 1896.

Mr. Reid's letter also seems to show that if buffaloes live in great numbers all along the bank of a certain river where tse-tse flies also swarm, and that if through persecution the buffaloes should be driven far up the river at certain times of year, only returning to their old haunts during the rains, when all hunters have left the country, a large proportion of the tse-tse flies do not migrate backwards and forwards with the buffaloes, but remain constantly on the section of the river where they first appeared as perfect insects, not appreciably decreasing in numbers as long as the buffaloes come amongst them periodically, but gradually dwindling in numbers, and at last altogether disappearing within a few years of the final extinction of those animals, in spite of the continued presence of other kinds of game.

Although Mr. Reid saw no "flies" between Leshuma and Kazungula either in 1885 or in 1888, there were still a few lingering there in the latter year. There were so few in the early part of 1888, however, that probably none were to be seen during June and July, when the nights were very cold, but later on in this same year they increased very rapidly in numbers, as I think, owing to the fact that my own and Mr. Reid's cattle deposited a great deal of dung all along the waggon track leading down to Kazungula. It was in June of that year (1888), after I myself had crossed the Zambesi on an expedition to the north, that Jan Weyers, an old Dutch hunter, took my waggon by night through the old "fly" belt between Leshuma and Kazungula in order to trade with the natives living on the Zambesi, sending the oxen back to Leshuma the following night. In the same month, or a little later, Mr. Percy Reid and his party brought their waggons to Leshuma, and their oxen pulled them backwards and forwards several times between that place and Kazungula. There was thus a great deal of cattle dung, which is, of course, precisely the same as buffalo dung, all along this short stretch of waggon road. For some reason this driving of cattle backwards and forwards between Leshuma and the Chobi caused an extraordinary increase in the number of tse-tse flies. All the natives who travelled the road remarked upon it, and both they and Jan Weyers assured me that they had thought the "fly" was almost absolutely extinct in this district, as in the previous year, even in the hot weather before the rains, very few had been seen.

However, when I went down to the river in August (1888) on my way to the Barotse country, I found a good many tse-tse flies along the track, and by November they had become very numerous. As Mr. Reid and his party did not return to Pandamatenka by way of Leshuma, but went along the southern bank of the Zambesi to the Falls, they were unaware of this sudden increase in the numbers of the tse-tse flies.

I am still quite unable to account for the sudden and rapid increase in the number of tse-tse flies along the waggon track between Leshuma and Kazungula between August and November 1888, as it is quite certain that up to the latter month they had taken no toll of blood from the cattle which had been driven backwards and forwards along the road either by night or during the cold weather in June or July.

I knew that my friend the late Dr. Bradshaw used to hold the view that the tse-tse fly deposited its eggs in buffalo dung, and I thought at the time that the cattle dung had been taken as a substitute. The very important researches, however, of Lieutenant-Colonel Bruce in Zululand have shown that "the 'tse-tse' fly does not lay eggs as do the majority of the Diptera, but extrudes a yellow coloured larva, nearly as large as the abdomen of the mother." The perfect insect does not hatch out for six weeks, so that the increase by generation from a small number of individuals in the course of a few months would not be very great. I can only think, therefore, that all the tse-tse flies throughout the bush through which the ten miles of road led from Leshuma to the Chobi must have been attracted to its neighbourhood by the smell of the cattle dung, which no doubt they mistook for that of buffaloes, the animals with which they have always been so closely associated in the countries to the south of the Zambesi. I am, however, not at all satisfied with this explanation.

I was obliged to keep my waggon standing on the bank of the Zambesi (waiting for ivory to be brought down from the Barotse valley) until late in November 1888, so that when I was at last able to send my oxen down to the river to bring it through the "fly," which now infested the waggon track leading from Leshuma to Kazungula in considerable numbers, the nights had become very warm, and although we did not start till after eleven o'clock, and ran the oxen to the river and brought the waggon back as quickly as possible, every one of them, twenty-one in all, got "fly-stuck" and died within six months.

After 1888 the tse-tse flies again rapidly diminished in numbers between Leshuma and Kazungula, and have long since absolutely ceased to exist there; so that here again we have another instance of a country in which, at no very distant time, both buffaloes and tse-tse flies literally swarmed, but from which both have now long since completely disappeared, although other animals, such as antelopes of various kinds and baboons, cannot yet be altogether extinct.

The same diminution and eventual disappearance of the tse-tse fly has also followed the extinction of the buffalo on the Okavango to the north of Lake N'gami.

As has been recorded by C. J. Andersson and other travellers and hunters, both buffaloes and tse-tse flies existed in great numbers along the Teoge (Okavango) river between Lake N'gami and LibÈbÈ's in the early 'fifties of the last century. At that time the Batauwana tribe were living at Lake N'gami. These people gradually acquired firearms and drove the buffaloes northwards up the Okavango, and the fly did not long remain in the countries which these animals ceased to visit. In 1884, after having been twice attacked by the Matabele, the Batauwana abandoned their settlements at Lake N'gami and retreated several days' journey to the north along the Okavango, where they built a new town, which they named Denukani (on the river). From this point they have now been hunting through all the country farther north for more than twenty years, and I have been lately informed that a waggon road has been cut from Denukani to LibÈbÈ's, and from thence to the Quito, the whole length of which is entirely free from tse-tse fly, which insects there seems every reason to believe have died out owing to the disappearance of the buffaloes from their former haunts.

But the facts which I have already stated, and which seem to me to show that in Africa to the south of the Zambesi there has always been a close connection between the buffalo and the tse-tse fly, by no means exhaust the evidence on this point.

When Sebitwane, the great chief of the Makololo, and Umziligazi, the founder of the Matabele nation, led their clans, the one to Linyanti between the Chobi and Zambesi rivers, the other to the high plateau near the sources of the Gwai and Umzingwani rivers, they found the whole country south of the Zambesi, between the Daka and the Gwai, occupied by an unwarlike and agricultural people akin to the Makalaka, and if any value can be placed on native testimony, these people were rich in cattle.

Attacked first by the Makololo and later on by the Matabele, these unfortunate people were killed in great numbers and gradually dispossessed of their lands, all their cattle being taken from them. Those that escaped death fled across the Zambesi, where their descendants are living to this day.

Now I have no doubt that long ago, before the country between the Gwai and the Daka rivers was settled up by natives, it had been a "fly"-infested country full of buffaloes. At any rate, as soon as the natives had been killed or driven out of it, buffaloes and all other kinds of game took possession of it, moving in no doubt from the countries both to the east and the west, and with them came a few tse-tse flies, which must soon have increased and multiplied in so favourable an environment.

In 1873 I was hunting elephants at the junction of the Gwai and Shangani rivers, and through all the country westwards to beyond the site of the present coal-mine at Wankies. At that time all this country was full of buffaloes and tse-tse flies.

Fifteen years later, however, the Matabele, who had then for a long time been in the possession of firearms, had driven the buffaloes out of all the country on either side of the river Gwai, and as these animals went farther north and east, the tse-tse fly gradually disappeared.

The last time I saw Lo Bengula alive—early in 1890—I spent the greater part of two days talking to him on many subjects, especially game, for he loved to talk about wild animals, having been a great hunter in his youth. He told me that there were then no more buffaloes anywhere in the neighbourhood of the Gwai and Shangani rivers, and that with the buffaloes the "fly" had gone too, and that as the buffaloes and the "fly" had died out, he had gradually pushed his cattle posts down both the Gwai and Shangani rivers, and that at that time, 1890, he had actually got a cattle post at the junction of the two rivers, where seventeen years before I had found buffaloes and tse-tse flies both very numerous.

The history of the country lying between the lower course of the Chobi river and the Zambesi has been very similar to that of the territory to the south of the Zambesi between the Gwai and the Daka.

When Livingstone and Oswell visited the chief Sebitwane in 1853, they first took their waggon during the night through the narrow strip of "fly"-infested country which ran along the southern bank of the Chobi, and swam their bullocks to the other side of the river before sunrise the next morning. Just where they struck the southern branch of the Chobi there were no trees or bushes on its northern bank, only open grass lands and reed beds to which the tse-tse flies never crossed, although the river was only fifty yards broad, and they simply swarmed all along the wooded southern bank.

At this time, 1853, Sebitwane, who possessed great numbers of cattle, was living not in the open grass country, which has always been free from "fly," but at Linyanti, which was situated beyond the northern branch of the Chobi and was surrounded on all sides by sandy ridges on which grew forest trees and bushes. In 1861 Linyanti was again visited by Dr. Livingstone, in company with his brother Charles and Dr. (now Sir John) Kirk. Sekeletu, the son of Sebitwane, was then the chief of the Makololo, and these people were still rich in cattle. After Sekeletu's death a civil war broke out between two rival claimants to the chieftainship which so weakened the Makololo, that a coalition of the remnants of the various tribes they had conquered and reduced to servitude some forty years previously rose in rebellion against their rulers, and under the leadership of Sepopo, the uncle of Lewanika, the present chief of the Barotse, absolutely destroyed them as a people, killing every male down to the new-born infants, but sparing all the young females and girl children, who were subsequently taken as wives by their captors.

After the destruction of the Makololo tribe, the country between the Chobi and the Zambesi was once more given back to nature.

In 1879 I crossed both branches of the Chobi and visited the site of the once important native town of Linyanti. I there found several relics of the ill-fated Makololo mission party (sent to that tribe by Dr. Livingstone's advice), in the shape of the iron tyres and nave bands of waggon wheels. At that time the surrounding country had been uninhabited for some fifteen years, and I found great herds of buffaloes grazing undisturbed all round and over the site of Linyanti, where once had pastured the cattle of the Makololo. With the buffaloes too had come the tse-tse flies, which swarmed all over this district, though when the former left the forest and bush and went into the reed beds and open grass lands between the two main branches of the Chobi, the latter did not follow them. There can be no doubt, however, that when the Makololo first crossed from Sesheke on the Zambesi to the northern branch of the Chobi river, they must have found both buffaloes and tse-tse flies numerous in the district where later on their chief Sebitwane built his principal town. The buffaloes must have first been driven to the west, and the fly must subsequently have died out, before the natives were able to introduce cattle into this part of the country. After the destruction of the native population about 1864, the buffaloes moved back into the country from which they had whilom been driven, and the tse-tse flies came with them. The rinderpest which passed through the country in 1896, I believe, killed all the buffaloes left anywhere near Linyanti, and probably the tse-tse fly has also long since died out in that district,[12] into which cattle may have been once more introduced by the natives, though I do not know that this is the case.

But although it would seem, from the historical facts I have just related, that in Africa, to the south of the Zambesi river, Glossina morsitans has always been dependent upon the Cape buffalo for its continued existence, certain climatic and other conditions which have never yet been satisfactorily explained have always prevented tse-tse flies from spreading into all parts of the country in which buffaloes were once found. In Southern Africa the tse-tse fly has always been confined to a strip of country along the south-east coast, and the hot, well-wooded valleys of the Zambesi and Limpopo rivers and their tributaries. Apparently the tse-tse fly (Glossina morsitans) requires a certain degree of heat in the atmosphere, or can only stand a certain degree of cold; for along the east coast it seems never to have existed to the south of St. Lucia Bay, in the 28th parallel of south latitude, although buffaloes were once plentiful far beyond this limit, all through the coast lands of Natal and the Cape Colony, as far as Mossel Bay. Nor are these insects ever found at a high altitude above the sea. "Fly" country is usually less than 3000 feet above sea-level, though in places such as the district to the north of Hartley Hills, in Mashunaland, tse-tse flies ascend to a height of nearly 3500 feet. Nearer the equator, they are able to live at a higher level, and I have myself met with tse-tse flies near the upper Kafukwe river at an altitude of at least 4000 feet above the sea.

The tse-tse flies spread with the buffaloes from the sea-coast all along the Limpopo to beyond its junction with the Maghaliquain, but were not able to accompany them to higher ground. The buffaloes, however, spread right up to near the sources of the Limpopo and its tributaries, crossed the watershed to the reed beds of the Molopo, and from thence spread through Bechwanaland as far south as the Orange river, hundreds of miles away from the nearest "fly"-infested area. Even in the midst of low-lying districts full of buffaloes, and, speaking generally, full of tse-tse flies as well, all open pieces of grass country, where there are neither trees nor bushes, and all reed beds of any size, will be found to be free from these insects. When buffaloes feed out into such places from the surrounding forests, the "flies" soon leave them and return to the shelter of the trees. Similarly, if one side of a river be covered with bush and forest down to the water's edge, and if, along this forest-covered bank, tse-tse flies swarm, these insects will never cross even a narrow channel to open reed beds or grass land on the other side. Dr. Livingstone has mentioned how, though he found tse-tse flies swarming along the southern bank of the Chobi river in 1853, his oxen were perfectly safe from these insects in the open grass lands on the other side of the river; and in my own experience, although I have often crossed this same part of the Chobi by canoe, and seen numbers of "flies" on meat, or on the natives or myself, as we left the southern bank, I never knew one of them to cross the river with us. As soon as we got to a short distance from the southern bank, they all left us and flew back to the shelter of the trees and bushes. But the most extraordinary thing about the tse-tse fly is, that in certain low-lying countries away from the wooded banks of the larger rivers, these insects were not found everywhere, but only in certain forest areas, known to the early South African pioneers as "fly" belts. I am speaking now, of course, of the time when natural conditions and the balance of nature had not been upset by North Europeans; for no charge of this kind can be made against the Portuguese, who were always poor hunters.

No one, I think, has ever been able to explain why the tse-tse flies never spread from the "fly" belt which was crossed by the old waggon road to the Zambesi, a few miles to the south of Daka, to the "fly"-infested forest, which lay across the same road a little to the north of Pandamatenka. The country between these two "fly"-infested areas was exactly similar in its vegetation, its altitude above the sea, and in every other particular, as far as one could see, to the "fly" belts which bounded it to the north and south, and during the rainy season buffaloes must have wandered through the intermediate country, as well as through the two "fly" belts. That tse-tse flies used to be found in the greatest numbers along the wooded banks of rivers such as the Chobi, the Zambesi and many of its tributaries, was owing, I think, to the fact that buffaloes had become excessively plentiful in the same districts, not because the near neighbourhood of water was necessary to them; for many "fly" belts, e.g. those extending across the road to the Zambesi, were absolutely destitute of water during several months of every year.

The tenacity with which tse-tse flies cling to certain tracts of country, or even narrow belts of forest, is wonderful, but they sometimes move beyond their usual limits nevertheless. About forty years ago, a waggon track was made by elephant hunters from Matabeleland to Hartley Hills in Mashunaland. Not more than ten miles to the north of the points where this waggon road cut the Umzweswe and Umfuli rivers, the country was always frequented by buffaloes and infested with tse-tse flies. In my own experience, I have often known large herds of buffaloes to come south along the Umfuli river up to and beyond the waggon road. I hunted and shot them there on horseback for the last time in 1885, and used my waggon and oxen to bring the meat and skins to my camp; and as my cattle did not suffer in any way, there could not have been any "flies" about. The tse-tse flies, however, used always to come with the buffaloes for several miles beyond their usual boundary, but gradually left them, and in my own experience I never knew them to quite reach the waggon road.

It will thus be seen that although "fly"-infested areas are, as a rule, well defined and well known to the natives, the movements of large herds of buffaloes may carry these insects—sometimes in great numbers—for a short period of time, for a few miles beyond their usual limits. Within a large area of country throughout which tse-tse flies exist, such as the level forest country in the valley of the Zambesi intersected by the lower courses of the Sanyati and Panyami rivers, or the country near the east coast, in the neighbourhood of the Pungwe river, tse-tse flies used to move about, so that in a place where they were found in great numbers on a certain date, hardly any would sometimes be met with in the same place a month later. In my experience, in such cases the tse-tse flies always moved about with the buffaloes, within these areas, where all other conditions were suitable to their existence.

In "fly"-infested areas where these insects are not very numerous, comparatively few or possibly none at all will be seen during the months of May, June, and July, when the days are short and not excessively hot and the nights are bitterly cold. In fact, it is quite possible to pass through a good deal of "fly" country during these months without ever becoming aware of the existence of these insects. But as the days get longer and hotter, and the nights less cold, if there are any tse-tse flies in a district at all they will be found to increase very rapidly in numbers. They become most numerous and most troublesome, I think, in October and November, just before the commencement of the rainy season. During the rainy season they are perhaps not quite so exasperating, but my experience has been that they were both numerous and troublesome at that season too. They are not so active in cloudy weather as in bright sunshine, and if a strong wind is blowing they hardly show themselves at all.

It is perhaps worth mentioning that the fact of the disappearance of the tse-tse fly from all countries to the south of the Zambesi, very soon after the complete extinction of buffaloes in the same regions, cannot be attributed to the settling up and cultivation of the land by Europeans; for the tse-tse fly has never existed in any part of Africa south of the Zambesi where malarial fever was not and is not still rife. Whatever may be the case to-day, up to 1896, long after the disappearance of both buffaloes and tse-tse flies, the Boers had never been able to establish themselves and live all the year round in the Northern Transvaal along the valley of the Limpopo, although they used to graze their cattle there during the winter; nor, as far as I am aware, although mining operations have been carried on for nearly twenty years within what was once "fly" country to the north of Hartley Hills in Mashunaland, has there been any settlement of families on the land in that district.

The word "tse-tse" (pronounced by the natives "tsay-tsay" and by colonists "tetsy") is simply the word used by natives of the Bechwana clans for the deadly fly known to scientists as Glossina morsitans. The Matabele—as well, I believe, as the Zulu—name for the same insect is "impugan." With the Matabele any kind of fly is an "impugan," but it is the only word they ever employ for the tse-tse.

As is well known, the tse-tse fly, when with its long proboscis it "sticks," as the Boers say, a domestic animal, introduces into the blood of the latter certain minute blood parasites (Trypanosoma), which, though constantly present in the blood of wild animals living in the "fly"-infested regions of Africa, does them no harm. These Trypanosomes, if introduced into the blood of domestic animals in any quantity, at once set up a disease, which almost always ends fatally. Cattle when "fly-stuck" soon begin to run at the eyes, and the glands behind the ears and in the throat swell. Although continuing to feed well, they become thinner and weaker day by day, and should they be exposed to cold or wet weather, their coats stare, as if they were suffering from lung sickness. According to the number of Trypanosomes in their blood, cattle will live a shorter or longer time. They will succumb within a month if kept constantly in country where tse-tse flies are numerous during that time. On the other hand, they will sometimes live for nearly a year if only "stuck" by one or a few flies whilst passing through a "fly"-infested belt of forest of small extent. I have known a young ox, though it showed every sign of having been impregnated with the "fly" disease—possibly it had only been "stuck" by one "fly"—to recover completely after remaining very thin for more than a year. Horses and donkeys, when "fly-stuck," run at the eyes and swell at the navel, and soon get thin and lose all their strength.

In 1877 I took three donkeys with me up the Chobi. They lived in a swarm of tse-tse flies day after day and all day long. The first of them to succumb only lived a fortnight; the second died in five weeks; but the third lived for nearly three months, and carried a buffalo head back to my waggons at Daka—some eighty miles from the Chobi.

For about ten days before the second donkey died I remained in the same camp. By this time it had grown very thin and was too weak to carry anything, but it did not seem to suffer in any way, and whenever I could observe it, was always feeding on the young green grass at the river's edge. I never tied it up at nights, but every evening it used to come and roll in a large heap of ashes behind my camp. One evening it came and rolled in the ashes as usual, but was too weak to get on its legs again, and on the following morning was dead. Apparently it enjoyed its life to the very last.

During 1887 some friends and I took four horses and five donkeys into the "fly" country on the Angwa river, in the northern part of Mashunaland. There were a good many buffaloes and a fair number of tse-tse flies in this district at that time, but not one for every hundred of either that I had met with along the Chobi river in the early 'seventies. My own horse cut its career short by galloping with me into an open game pitfall and breaking its back, and the other three, although they were well fed with maize morning and evening, were too weak to gallop after game in a fortnight. After a month they were too weak to carry a man at all, and they were then shot. The five donkeys all got thin, and swelled at the navel, and ran at the eyes, but none of them died, although they remained in the "fly" country for more than a month. By the end of the following rainy season they had quite recovered their condition and were well and strong again. These same five donkeys were taken down to Zumbo on the Zambesi the following year by the late Bishop Knight-Bruce. But they all died from the effects of this journey, during which they must have suffered great hardships and also been exposed to the attacks of thousands of tse-tse flies on the lower Panyami river.

When visiting the old Portuguese settlement of Zumbo on the Zambesi, in 1882, I found the few Portuguese residents as well as the natives living there in the possession of great numbers of pigs. These animals were sent out every morning into the country round the settlement, and called back in the evening—those which belonged to the Portuguese—by a few notes on a horn. A little maize was then scattered on the ground for them to pick up, after which they were shut up for the night in a walled enclosure. As tse-tse flies were numerous along the bank of the Zambesi on both sides of Zumbo, and it was quite impossible to keep cattle there on account of them, or any other domestic animals besides the pigs, except the small native goats, the former must have been equally as resistant to "fly" poison as the latter. These domestic pigs certainly did not owe their immunity to the "fly" disease to the fact that they were fat, for they were miserably thin long-snouted looking brutes. Although the pigs I saw at Zumbo probably did not go very far away from the settlement during the daytime, I feel sure that they must have been constantly bitten by tse-tse flies, as these insects were numerous quite close up to the native village, which is built amongst the ruins of the old Portuguese town.

All the natives living in "fly"-infested districts of South Africa keep small, miserable-looking dogs, as well as goats of a small, indigenous breed, and the natives outside such infested districts also keep goats of the same kind. These goats take no harm from the tse-tse flies; but the large Cape goats, which are descended from European breeds, as well as Angora goats, are not resistant to the "fly" disease. Nor are any dogs of European breeds.

In 1891 my two horses were suddenly attacked by tse-tse flies as I was riding with a companion along the bank of the Revue river, where the local Kafirs had told me these insects did not exist. Luckily, being so well acquainted with the peculiar "buzz" made by a tse-tse fly, I believe I heard the first one that came to my horse, and immediately dismounted. In the next few minutes we caught sixteen flies on the two horses, most of them by pinning their feet with a knife blade, as they are very difficult to catch with the hand. I then made the Kafirs cut branches, with which they kept the flies off the horses until we had got them away from the river, and beyond the "fly" belt. Most of these flies were caught immediately they settled on the horses, but two or three managed to fill themselves with blood. My horses, however, which were in very good condition, were never affected in any way.

Tse-tse flies are most active and troublesome in hot weather. During the winter months in South Africa (May, June, and July) none will be seen until the sun is high above the horizon, but later in the season they begin to bite early in the morning. After sunset in the evening they seem to become lethargic, and will often crawl up between one's legs or under one's coat as if for shelter, and from such positions will often "stick" one long after dark. On cold nights they probably become quite benumbed, and do not move at all, but on warm nights they are sometimes very active and hungry. As before related, I lost twenty-one oxen by driving them backwards and forwards in one night through a "fly" belt ten miles in width. This was in the month of November, and the night was very warm.

On the 25th of August 1874, when returning from the pursuit of a wounded elephant, I struck the Chobi river late at night, and had to walk several miles along the bank before getting to my camp. It was a bright moonlight night, and fairly warm. My only clothing consisted of a shirt, a hat, and a pair of veld shoes, and as I walked along near the water's edge the tse-tse flies kept flying up from the ground and biting my bare legs, and from the loud slaps behind me I knew they were paying similar attentions to my Kafirs. Now, these "flies" were undoubtedly resting on the bare ground, for we were walking, not through bushes, but along the strip of open ground between the forest and the water's edge. The bite of the tse-tse is very sharp, like the prick of a needle, but in a healthy man it causes no swelling or after irritation, like the bite of a midge or a mosquitoe. Speaking generally, the bites of a moderate number of tse-tse flies may be said to have no appreciable effect on a human being. Still, I am of opinion that if one is exposed to the attentions of swarms of these insects for months at a time, the strongest of human beings will find himself growing gradually weaker. Explorers or traders may sometimes be exposed to the bites of great numbers of tse-tse flies for a few days together, but they will soon pass through such districts. Only an elephant hunter, I think, would ever be likely to remain for any considerable period of time in a country where tse-tse flies were very numerous. I cannot think that many Europeans have suffered from tse-tse fly bites as much as I have. In 1874, and again in 1877, I spent the whole of the dry season, from June till November, on the southern bank of the Chobi river, and lived during the greater part of those two seasons in a swarm of tse-tse flies. Up to that time I had had no fever, and my constitution was unimpaired in any way. Towards the end of both those seasons, however, not only I myself but all my Kafir attendants became excessively thin, and seemed to be getting rather weak. The natives, too, who lived in the reed beds where there were no tse-tse flies, but who used to come to the southern bank of the river to collect firewood and look at their game traps, all said that they could not live there because of the tse-tse, which made them thin and weak, or, as they expressed it, the tse-tse "killed them," just as they say in times of famine that hunger is killing them.

In 1882 I met with a curious experience, for which I cannot quite account. During that year I had made an expedition from the high plateau of Mashunaland to Zumbo, on the Zambesi, and had had a somewhat hard time and gone through a severe attack of fever. I had also been very much bitten by tse-tse flies on the lower Panyami and Umsengaisi rivers. Towards the end of the year I got back to the Mission Station of Umshlangeni in Matabeleland, and was given a warm welcome by my old friends the Rev. W. A. Elliott and his wife. I reached the Mission Station late in the evening, after a ride of fifty miles in the hot sun. I was fairly well, having recovered from the attack of fever, but perhaps a little run down.

Soon after I had turned in on the bed Mrs. Elliott had arranged for me, I felt my nose coming on to bleed. Not wanting to disturb any one, I pulled a newspaper I had been reading from the chair by my bedside, and spreading it on the floor, let my nose bleed on to it. It bled a good deal, and the next morning I was surprised to see that the blood which had come from me was not like blood at all, but slimy, yellow-looking stuff. When I showed it to Mr. Elliott, I said to him that it looked to me exactly like the blood of a "fly-stuck" donkey which I had shot some years before at Daka, and I laughingly suggested that I was "fly-stuck" too. That something had affected the red corpuscles of my blood seems certain, but whether innumerable tse-tse fly bites or fever, or both combined, had done it I cannot say. Ever since I received an injury in the head in 1880, I have been rather subject to bleeding from the right nostril, but I have never again lost any blood which bore the slightest resemblance to that which came from me in Mr. Elliott's house after my trip to Zumbo in 1882.