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definite purpose in view, and move back, after drinking, in a similar manner. This movement must result in large numbers of fly being carried across, and, though there is no doubt that flies thus carried generally return to their previous haunts, a constant movement of this nature may result in larvæ being deposited near the Kana, the flies from which would have no tendency to move back to the Mzola, and in this way the pest might become established on the Kana at points where the game come down to drink. I should anticipate that only regular movements of large numbers of game would be likely to carry the fly over in this manner, as the chances of young being deposited in a new area in sufficient numbers to start a new colony are very small, especially as females close to parturition are probably very rarely carried any distance. The foregoing is, of course, merely theory, and be wide of the mark, but it is of interest to record the facts and a possible explanation.

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Outbreak of Trypanosomiasis on Meare's Farm-Sikombella River. This is a matter of extreme interest, inasmuch as it constitutes, for all prac tical purposes, a natural proof that trypanosomes of the 7. pecorum type are capable of being transmitted from an infected to a healthy ox by some agency apart from tsetse fly, a theory that was first put forward by Dr. Yorke, I believe, in 1909, but has not been definitely proved by experiment. I have, of course, repeatedly stated that a similar method of transmission has apparently been at work in the Hartley District for some years past.

The facts of the outbreak on Meare's Farm, without going into details, are struck" in a known fly roughly as follows:-In October last certain oxen were belt near the Sasame River and all subsequently died. Of the oxen with which they mixed before their death twelve contracted the disease and died during These oxen were not December, after the return of the oxen to Meare's Farm.

known to have encountered fly. In March, twenty oxen contracted disease at Meare's. In February, five young oxen were introduced into a span to go to Gokwe, returning about 1st March; these five all showed signs of sickness and two died, being diagnosed by Bevan as "fly struck." In April two milch cows that had never left the farm contracted typical fly sickness and died, and other cattle, including a bull, that had not left the farm, became sick later.

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Now the road from Que Que to Gokwe, which runs through Meare's Farm, has been traversed regularly by the Government ox transport and that belonging to the Inyoka and Swiswi tobacco farms for some years past, and is entirely free from any suspicion of being infested with tsetse, whilst the route by which the runs clear of fly for a oxen returned from where the first eight were "fly struck

It is thus out of distance of at least eighty miles before reaching Meare's Farm. the question that fly could have followed the oxen back to the farm.

Cattle have lived in a healthy state at Meare's Farm and near by for a number of years, and until the introduction of fly-struck cattle there was never If no other agency any thought of fly within a radius of about thirty miles.

than tsetse were at work the only explanation could be that the fly had moved down from the belt to the north. I spent three days at the farm looking for fly in the most suitable places with negative results, and then travelled straight across country towards the belt on the Umniati, going down the Gwanyika River and on I then went down the Umniati to Robb's Drift, seeing no sign of fly en route.

and encountered no fly until my arrival at Ngatsuru's Old Kraal, which was marked I returned by the Mtanka River, thus as the southern limit of this belt in 1914. traversing the two routes by which fly could have spread towards Meare's, both proving quite free from fly. Whilst it is not possible to establish a scientific negative with regard to the absence of tsetse from a given piece of country in so short a time, these observations, in conjunction with the statements of hunters and natives, and the known freedom of this area from fly since the rinderpest, leave no practical doubt that the infections at Meare's Farm were not due to any extension of the fly area to that locality. The attached map will, I hope, make the situation clear.

Suggested Experiments re Game exclusion from Sipani Vlei.

As arranged with His Honour the Administrator at the conference held on 14th February last, made a careful inspection of Sipani Vlei, with a view to ascertaining its suitability for an experiment to determine the effect of excluding game from a fly belt which is of an isolated nature during the latter half of the

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dry season. I find that this vlei, and the type of forest depending upon it, is about a mile in length and about a quarter of a mile in extreme width. surrounded on all sides by forest, which was quite leafless at the time of my visit (23rd and 24th August), and was in a similar condition on the two previous occasions I was there, the last visit being as late as 20th November. There is thus every reason to believe that this belt is isolated from July to the end of November. gusu type, the On the south-east side and south-west end the forest is of the " remainder being mopani and sinanga (thorn thicket). The only difficulty that would be met with in erecting a fence would be on the lower or north-west side, where the ground is broken to a shallow depth by four dry watercourses, This difficulty could draining the vlei during the rains into the Sabala River.

be surmounted without much trouble. About a thousand yards from the north-east end of the vlei is a small "pan" containing water and surrounded by less than These trees would need to be cut a dozen trees in foliage, which shelter tsetse. down. A fence ten miles in length would enclose the required area in a satis- factory manner.

Mr. Zunekel, of the Native Department, expressed the opinion that a ten-mile fence of the palisade type, such as certain sections of the natives are in the habit of building round their kraals, could be erected for from £400-£500, provided that two or three hundred natives were turned out for the work. The only expense would be the wages and food of the boys. If this fence were built of mopani, of which great quantities exist in the neighbourhood, it would be of quite a lasting nature.

The great drawback is, of course, the remoteness of the spot. It is three-and- a-half days from Gokwe. This leads to a certain amount of doubt as to whether the experiment could be efficiently controlled. The fence would need to be kept in constant repair, and any animal that broke in would need to be destroyed. İn Whether this addition no natives should be allowed to enter the fly-infested area. could be attained by placing a couple of superior native messengers, with reliable assistants, in charge, it is difficult to say. Apart from this drawback, Sipani Vlei, from its limited extent, intense infestation, and isolated position in the dry season, is admirably suited for an experiment which would, if effectively carried out, supply very valuable information on the relation of big game to tsetse fly.

RUPERT W. JACK,

Government Entomologist.

11141

No. 76.

MINUTES OF THE TWENTIETH MEETING OF THE FINANCE SUB- COMMITTEE OF THE IMPERIAL BUREAU OF ENTOMOLOGY, HELD AT THE COLONIAL Office on 22ND FEBRUARY, 1917.

Present:

DR. HARMER, (Chairman).

SIR D. PRAIN.

MR. READ.

DR. MARSHALL.

MR. FINDIAN (Acting Secretary).

THE minutes of the Nineteenth Meeting* were approved.

The acquisition of new premises, which Dr. Marshall and Mr. Neave were authorized at the previous meeting to effect, was formally reported to have been additional room in the an It had been found that carried through. Elvaston Place house would cost £180 a year during the War, and £175 after- wards; whereas, at 89, Queen's Gate, more extensive and more convenient accom- modation could be obtained for £150 a year. Arrangements had therefore been made to take a five years' lease of the latter premises.

The Sub-Committee discussed the question which the meeting had been called to consider, namely, the release of further members of the staff of the Bureau for military or other war work.

Dr. Marshall explained that, of the men on the staff of the Bureau (nine in number), two were above and one below military age.

* No. 72.