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The investigations were carried out in the Inland Savanna Forest Zone of the Northern Territories of the Gold Coast, the climate of which is characterised by extreme variations in rainfall and relative humidity between the wet and dry seasons.Glossina palpalis and G. tachinoides are widely distributed along the waterways throughout the zone. They come into intimate contact with the human population and are, in consequence, the most important vectors of human and animal trypanosomiasis.G. morsitans submorsitans occupies unpopulated and thinly populated regions and so, coming more rarely into contact with man and cattle, is a less important vector of trypanosomiasis.A pandemic of sleeping sickness, with 30,000 square miles of heavily infected country, lies across the upper reaches of the Volta rivers and involves parts of the north of the Gold Coast. In the areas studied high rates of infection (4–7 per cent.) were found associated with serious population declines which have given rise to secondary evils, the invasion of G. morsitans into depopulated parts and the concentration of populations on the watersheds between infected river valleys, with resultant over-farming, erosion and lowering of the standard of living.The results of two methods of controlling G. palpalis and G. tachinoides were studied : (1) “ Protective Clearings ”, aimed at breaking the contact between the tsetse and man or cattle at certain points only ; (2) “ Eradicative Clearing ”, aimed at the complete removal of tsetse throughout an area.The effects of protective clearings on the fly were as follows : Clearings less than 300 yards in length are considered useless, and may cause an increase in fly-incidence by forming artificial feeding grounds. Clearings of 440 yards can effect up to 70 per cent, reduction in fly-incidence measured over a long period, but for several months of the year show no reduction or may even show an increased incidence. Clearings up to 880 yards long can bring about 60–90 per cent, fly reduction, but at two periods during the year, at the end of the dry season and in the middle of the rains, their effectiveness is considerably lowered by the invasion of hungry flies into the clearings. Clearings over a mile in length exclude all but a few vagrant flies, but even five miles of clearing are traversed by occasional flies.A study of the effects of various applications of protective clearings on the incidence of sleeping sickness led to the following conclusions. To have any value protective clearings must be made in as many places as possible over a wide area. They effect no general reduction in the disease if applied at a few places only. Small clearings, averaging 400 yards in length, if made consistently over a large area, can effect up to 40 per cent, reduction in sleeping sickness in 4–5 years, after which the disease tends to become stabilised at the lower level. Long clearings, averaging 1,000 yards, almost double the rate and amount of reduction, effecting 70 per cent, reduction in three years, but the tendency for the disease eventually to become stabilised remains. Clearings over a mile in length at each village caused a reduction of 85 per cent, in one area.Protective clearings alone are considered unlikely to be able to effect complete control in areas of serious endemic sleeping sickness. They do not entirely exclude the fly, and they do not touch all the points where the transmission of infection takes place. Further disadvantages arise from the fact that, to attain maximum fly reduction, all vegetation, including tall trees, should be cut. This is expensive and difficult and may lead to erosion and the silting up of water-holes, thus driving the people back to uncleared parts of the river. Finally, animal trypanosomiasis can never be controlled by localised clearings, therefore improvement in animal husbandry, and consequently in agricultural practice and nutrition cannot be fully realised.Eradication of G. palpalis and G. tachinoides is based on the consideration of the tsetse community of a complete river system as a natural biological unit. During the prevalence of the adverse climatic conditions of the dry season, the breeding and survival of tsetses are possible only in certain restricted habitats from which the flies spread extensively along the water courses during the rains. The dry-season habitats are confined to definite plant associations that are characterised by a limited number of species of trees and shrubs. The removal of only these species throughout a river system renders the habitats untenable during 4–6 months of the dry season and results in the disappearance of the whole fly community.By the method of selective clearing, 1,050 square miles of country in the northwest corner of the Gold Coast were freed from tsetse between December, 1940 and March, 1945. On the main river of this region, the Kamba, which was cleared by 1942, routine catching after clearing showed 1–8 flies per year in places where the pre-clearing averages had been 2,700–7,500 flies per year. After the clearing of some neighbouring fly-belts, these occasional captures ceased. Wet-season migration from the uncleared Volta, however, brings small numbers of flies 5–9 miles up the lower reaches of the cleared river.The incidence of sleeping sickness for the Kamba area fell by 92 per cent, between 1938, the year before the start of control measures, and 1944.Along the Kamba, 160 square miles of land which had become depopulated through trypanosomiasis is being developed voluntarily by the natives, by farming, grazing, etc. Approximately 1,000 people have settled in parts of this area since clearing was finished.In 1939 G. morsitans invaded the depopulated area, and increased greatly in numbers in the following years. The spread was checked, and finally a high degree of control was established by the disturbance of big game and its reduction in numbers. Settlement of the thinly populated country is needed to consolidate this control.Selective clearing can be followed by the eradication of essential dry-season habitat vegetation which will enable maintenance to be put on a long-term rotation of about ten years. Permanent reclamation is a possibility that is now being studied.The relative merits of medical and entomological methods of controlling sleeping sickness are discussed. Mass treatment can have great success, but fails to control under difficult conditions, and has not yet been found able to eliminate the disease. The addition of adequate tsetse control increases the effect of mass treatment. Eradication of the fly is capable of eliminating the disease and does not require the addition of mass treatment to bring this about.The removal of tsetse throughout the river system, as in selective clearing, has the following additional advantages : It makes possible a sound agricultural development based on the possession of good quality livestock; this reflects also on nutrition. It enables the population to live with impunity in the vicinity of permanent water and, by spreading out at a density optimum for their type of agriculture, to avoid concentrations at local clearings or on dry, hilly country away from rivers; thus the possibilities of over-farming and erosion are avoided and the watersheds and headwaters can be reserved for afforestation. By these means, instead of ground being abandoned to the tsetse, the fly is replaced by a healthy agricultural population.

SUMMARY: Tracer sheep were used to determine the temporal distribution of acquisition ofF. hepatica on both irrigated and non-irrigated areas an area of northern Victoria where this parasite is endemic, for the period November 1974 to November 1976. Throughout the study, very few flukes were acquired on the non-irrigated experimental area, and of this small number most were acquired by sheep in late spring and early summer. Flukes were acquired throughout both experimental years on the irrigated experimental area. The intensity of infection was lowest in late winter and early spring, but acquisition was substantial when measured over a year, being 483.5 in the first year and 1234.6 flukes per sheep in the second year. The productivity of these animals was lower than that of equivalent animals kept on an area free of fluke, but quantitative interpretation of this information is confounded by the effect of the presence of an area with atypically high moisture levels (the snail habitat) on pasture production in the area grazed by the infected animals. The differences recorded are therefore likely to be underestimates of the true difference. A suitable treatment regimen for control of liver fluke in sheep in northern Victoria is outlined.

The productivity of 24 Corriedale weaner wethers in eight groups of 3, artificially infected with a range of fluke burdens, was studied by measuring body weight change, midside patch wool growth, fleece weights and feed digestibility over a period of 24 weeks. Data from bodyweight and patch wool measurement and feed digestibility were analysed by regression procedures. All parasitised groups exhibited a reduction in growth rate, patch wool growth and fleece weight, when compared with the control groups. Reduction in feed conversion efficiency was detected in groups having mean burdens of 45, 67 and 117 flukes. Because groups with mean burdens of 230 or more flukes had reduced feed intake, and sheep in these groups died, the feed conversion information from these groups cannot be considered unequivocal. The group mean liveweight changes, patch wool growth and fleece weights were closely related to the mean number of flukes in the respective group. Prediction equations for wool growth rate and body weight gain in fluke infected sheep are presented.

Economic benefits obtained from two schemes for the anthelmintic control of helminthiasis in breeding ewes and their lambs have been assessed in the Western District of Victoria. The results were compared with those from sheep receiving no anthelmintic treatment, and also with those from sheep given anthelmintic every 2 weeks. The results reported in this paper cover the wool-growing years 1971–1972 and 1972–1973, and represent the continuation of a study commenced in 1970. The “critical” treatment scheme yielded the highest net return under all circumstances in both years. The actual net benefit per 100 sheep, in comparison with “no treatment”, was A$213 and 255, respectively; results which were not sensitive to variation in wool prices or animal productivity. The benefit was derived principally from higher fleece weight per ewe, higher prices per kilogramme for better quality wool and, to a lesser extent, from higher values for ewes and lambs. Because net returns from “traditional” treatment groups were lower, A$ 95 and 103, respectively, and were sensitive to variations in animal productivity, this scheme could not be recommended for routine use.

SummaryA detailed study of the bionomics ofGlossina longipalpis, Wied., was undertaken at Takoradi, the principal port of the Gold Coast in West Africa, and lasted from February to September 1931.The topography of this country is undulating; the vegetation is of Transition Forest type, intermediate in character between Rain Forest and Savannah Forest, and of an exceedingly dense, homogeneous nature, with a few small glades in the forest, and interrupted by large open marshes on the lower and flatter ground.The climate is remarkably equable, with a low mean annual rainfall between 40 and 45 inches, but constantly high humidities, owing to the moisture-laden sea-winds. There is a double rainy season, the main rains from April to July, and a second shorter period of rainfall in October and November.There is a rich mammalian fauna, with the exception of the larger game animals.Three species ofGlossinaoccur:G. longipalpis, Wied., the commonest, evenly distributed throughout the bush, and the only species dealt with in this paper;G. palpalis, R.-D., confined to water-courses and the edges of lagoons; andG. medicorum, Aust., rarely met with.Two isolated fly-belts, identical in every way, were studied. In one, section A, flies were caught and killed daily; in the other, section B, the control area, the flies were liberated after noting the catches. By September, the tsetse population of A had been reduced to less than one-third of that of B, presumably the effects of catching and killing.The main food hosts of this species were the bushbuck and duiker, ubiquitous in this forest. When these small game animals were driven out of a third fly-belt, section C, by farming and wood-cutting, the fly quickly and completely disappeared. This species was never found to feed on reptiles, although they were common in the fly-belts.Meteorological observations in the open country and in the fly-belts showed a consistently lower temperature and higher humidity in the latter, as well as its greater equity in these factors. The movement of the fly into the open was apparently governed by humidity, the greatest movement taking place when the humidity of the open was within the normal range of fly-belt humidity.By statistical methods, coefficients of correlation were determined for the fly's density-activity and various climatic factors of the fly-belt. The fly showed a high positive correlation with temperature, and a lower correlation with humidity, of which saturation deficit was a better index than atmometer evaporation. There was a significant correlation with sunshine, but none with rainfall. This correlation with humidity was mainly a temperature effect, as was also the correlation with sunshine. Temperature was evidently of major importance. There was a significant negative correlation between fly and relative humidity, measured with a wet and dry bulb hygrometer in a screen in the open.All correlations were greatest when considered direct, the fly catches with simultaneous climatic readings, indicating that these factors influence the activity of the fly in this way, rather than its density. The fly was found to be inactive at temperatures below 74°F., with high humidities of 80 or 90 per cent. or over. This explains the major influence of temperature, shown by the methods of correlations. The temperature range in the fly-belt, during the period of observations, was close to the temperature significant for the fly's activity, and therefore variations produced marked reactions; the humidity range was much closer to the fly's optimum and therefore better tolerated.There is marked daily rhythm in the fly's activity, which is only influenced by climate under extremely unfavourable conditions of temperature or humidity.The distribution ofG. longipalpisin the Gold Coast is dependent upon the humidity of the ecoclimate, rather than upon temperature. It occurs in three main vegetational types—Transition Forest, Inland Savannah Forest, and Coastal Savannah— where the range of humidities is between 50 and 80 per cent. R.H., and temperature between 75° and 85°F. It does not occur in the Rain Forest, where the relative humidity is constantly above 80 per cent., or in northern Savannah, where the humidity is as low as 30 per cent, in the dry season.The main breeding season was from March to July with its maximum in May, at the height of the rains.This species was found infected withTrypanosoma gambiense,T. congolense, andT. vivaxat Takoradi, and is probably second in importance toG. palpalisas a vector of sleeping sickness in the Gold Coast, but at present of less importance thanG. palpalisorG. tachinoidesin the transmission of trypanosomiasis of stock.The receding of the Ashanti forest and the present development of the Colony may cause even greater contact between this species of tsetse and man. The main policy for control should lie in improving and controlling the natives' methods of cultivating the bush. Farms should be as close to the village as possible, contiguous, and kept under cultivation, if possible, permanently. Clearings should be made of at least 100 yards width round bush villages, and of at least 200 yards width round important towns. Small clearings and isolated farms are considered a danger.

A combination of historical, geographical, and epidemiological studies has given sufficient insight into the ecology of sleeping sickness to enable the main factors influencing the development and spread of an epidemic to be traced.The evidence shows that in West Africa sleeping sickness is not primarily a disease of the forest, where tsetse flies are most abundant, but belongs essentially to the dry country in the north of the savanna woodland zone, where the earliest occurrences and severest outbreaks have been located.The first mention of sleeping sickness comes from the upper Niger and dates back to the 14th century. By the beginning of the present century intense though localised epidemics were devastating parts of the Mossi, Grounsi and Lobi country of the upper Volta rivers. At this time the disease was unknown on the coast and of sporadic occurrence only in the forest. A severe trans-Volta epidemic covering 60,000 square miles, developed between 1924 and 1940, but was confined to the north of the inland savanna zone with nothing comparable in the forest.The epidemic spread in three principal ways : (1) Outwards from original foci of infection because of the dynamic nature of the disease. This produced a concentration of infection around headwaters, a feature characteristic of advanced epidemics. (2) Through the agency of travellers, originally from north to south but subsequently in both directions : a rapid method of spread producing linear distribution of infection along trade routes. The tempo was greatly increased on the pacification and development of West Africa after 1900. (3) A gradual southward shift in the main epidemic zone appears to be resulting from a long-term change in the African climate which is combining with man's activities to produce a southerly extension of xerophytic vegetation types and a regression of forest.The most important spread was that caused by the trading caravans, more especially the cola traders, who have been coming down to the cola-nut areas in the Ashanti forest from the big markets on the Niger and Upper Volta since the 11th century. The caravans were formerly very large, up to one or two thousand strong, and were frequently made up of Mossi and Grounsi from the territory that was so heavily infected by the beginning of the present century. It is certain that a continuous introduction of infection would have been taking place into the forest ever since trypanosomiasis was prevalent in the north, that is for 100 years at least. And infection has been known in the forest for about that period, yet always to a mild degree, never reaching epidemic form. It has been sought for, because conditions in the forest, with the vector Glossina palpalis in contact with every village and path, appeared to be ideal for the transmission of infection and this drew the particular attention of the early workers from 1908 onwards. But the most that could be found was a threatened epidemic in north-west Ashanti, very significantly centering on the big cola markets which formed the termini for the northern traders.This historical evidence and the reasoning from epidemiology lead to the conclusion that conditions in the forest are not conducive to the development of epidemic sleeping sickness and that the low state of endemicity found there is maintained by the constant introduction of infection from the true epidemic areas in northern savanna.From this conclusion arises a practical point of the greatest importance. If the sources from which infection is introduced into the forest could be eliminated the disease there should eventually die out and the tsetse, from the human point of view, would be harmless. Tsetse control in the forest may prove difficult and expensive, and if it is attempted by clearing this might end in the literal destruction of the forest. Such measures would be hard to justify, so many other factors of possibly greater importance than trypanosomiasis are involved, both the intrinsic value of a forest for its products and the wider value through its influence on climate, soil and water.In formulating a plan for the control of sleeping sickness, the habits of both vectors, human as well as insect, should be considered. The tsetse plays a major role in the development of the high infection rates characterising the epidemic outbreaks in northern savanna ; the human vector distributes infection from these sources along trade routes and into the forest. The elimination of the disease at its source, in true epidemic centres, which can be most effectively accomplished by eradication of the tsetse, will check the distribution of infections to the secondary areas of lighter infection which could then be cleared up by quite minor control measures or might even disappear spontaneously.This plan is now in operation in the Gold Coast. The validity of the arguments on which it was based is being shown by the results that are already apparent : the high rates of reduction in the epidemic areas and the pronounced lowering of infection in neighbouring, uncontrolled areas, more particularly in the forest region of north-west Ashanti where it is entered by a trade route coming from the previously heavily infected country.

1. Primary fly-belts round Makongo consisted of three different vegetational communities: a Cynometra-Vitex association along the main length of the Makongo river, on a clay soil; a Ficus congensis association along the river close to the town, on a sandy soil; and Isoberlinia doka woodland on moist sandy soil north-west and south of Makongo.2. Secondary fly-belts of less dense vegetation occur in the orchard bush savannah round Makongo, and these are not colonised until the commencement of the rainy season.3. Glossina tachinoides and G. palpalis both occurred in the riverside communities, and G. palpalis alone in the Isoberlinia woodland.4. Along the river G. palpalis outnumbered G. tachinoides by 3:1 in the dry season. At the commencement of the rains G. tachinoides increased more quickly than G. palpalis, bringing their numbers very nearly equal, but at the end of the rains there was a decrease in G. tachinoides which restored the original proportion.5. G. morsitans had been found at Makongo formerly but was not met with at the time of this investigation, its absence being due to the disappearance of the larger antelope from the neighbourhood.6. Smaller game animals, small mammals and reptiles afforded an adequate food supply for tsetse in the fly-belts, and also passing herds of cattle, as well as natives from the village and travellers.7. The distribution of G. palpalis within the fly-belts was markedly influenced by the proximity of a cattle road along which herds of cattle passed almost daily, and by village water-holes.8. During the dry season the primary foci were always found to be the places of greatest relative humidity, and the fly does not tend to move out of these until the general atmospheric humidity has reached a certain fairly high degree.9. In clearing the fly-belts the removal of all primary foci within a quarter of a mile of the town and of thick bush within 100 yards of water-holes was undertaken. The work lasted from the beginning of February to the end of March 1931.10. The effect of clearing the Isoberlinia doka woodland was to banish G. palpalis completely, and it never returned to these clearings.11. On clearing the riverside Ficus congensis fly-belt, G. tachinoides was practically eliminated for the first three months, but reappeared in the clearings in June when there was a general increase and up-stream migration of this fly. G. palpalis remained in this clearing in fluctuating numbers up to June, when observations were suspended.12. 565 marked tsetse were liberated in the fly-belts immediately previous to clearing. Of G. palpalis 12·7% were recaptured in the clearings and 11% outside the clearings. Of G. tachinoides 5·5% were recaptured in the clearings and 6·8% outside.

In an area of sleeping sickness due to Trypanosoma rhodesiense in Uganda, Morris's ‘ animal ’ traps were used to study the activity and the relations with habitat and hosts of the vector, Glossina pallidipes Aust., a tsetse difficult to sample by conventional fly-round methods.This type of trap was found to give samples both numerically greater and more truly representative of the tsetse population present than did either fly-boys or Chorley's bicycle screen.Black traps showed an over-all superiority to brown traps, greatest during the rains and disappearing in the dry season, and this was related to the tsetse being attracted by the trap as representing a natural host.

Cocoons of Diprion sertifer, Geoffr., containing nearly eight millions Microplectron fuscipennis, Zett., were collected in Europe in 1934 and despatched to Canada for the control of the Spruce Sawfly, Diprion polytomum, Htg.This parasite is widely distributed throughout Europe as a primary parasite of several species of pine sawflies of the genus Diprion.A full account of the biology and a detailed description of the various stages is given.In the laboratory it was reared in large numbers on the cocoons of D. polytomum from Canada.Its chances of success in Canada depend on its acclimatisation and the accessibility and quantity of host material. Its tremendous fecundity and rapid rate of increase are greatly in its favour.

SummaryA detailed tsetse-fly survey of 41,000 sq. miles in the inland savannah zone of the Gold Coast (Ghana) was completed in five years using an entirely African staff and working only six months each year.This undertaking was made possible because studies of the species of Glossina concerned, G. palpalis (R.-D.), G. tachinoides Westw. and G. morsitans sub-morsitans Newst., had provided knowledge of their habitat, food-hosts and activity rhythm, on which could be based a standard yet simple survey technique, within the compass of independent native teams.The restricted activity rhythm of the flies, subject to both daily and seasonal variations, meant that nothing less than a ‘day’ of eight hours of observation could be accepted as a valid sampling unit.With tsetse flies at low densities, a day's search was inadequate, giving only 40 per cent, reliability compared with 6-day observations. Four days' search gave 90 per cent, reliability and was adopted as the minimum period of search.Each survey team was under the charge of a Kecorder or Field Assistant, with fly-boys devoting the whole of their time to catching. Comparability of survey data was ensured by keeping teams to the same size, two fly-boys being the optimum, since it was found that the size of the catch was not always proportionate to the number of boys, the relationship varying according to a variety of factors.In surveying G. palpalis and G. tachinoides the ‘picket’ system of more or less stationary teams, measuring their catches by the ‘day ’, was found overwhelmingly superior to the ‘fly-round’ technique.The survey procedure described for savannah woodland country was not effective in sampling G. nigrofusca Newst. in the Ashanti forest or G. longipalpis Wied. in the coastal savannah, but Morris's ‘animal’ traps were found to take both species readily in places where they had not been detected or only occasionally caught by fly-boys. Experiments showed that trap catches were superior, both numerically and in giving a more representative sample of the tsetse population present. It was also shown that trapping could be a valuable means of studying the biology of these two ‘man-shy’ species of Glossina. Traps were also effective in taking G. pallicera Big. and G. medicorum Aust.The greater value of traps compared with fly-boys as a means of sampling various species of tsetse fly is discussed, and suggestions are put forward for developing trapping as a method of survey.The type of trap employed is regularly catching insects of several other families, including a number of species among the Tabanidae, and of several other orders.

A severe outbreak of the Spruce Sawfly (Diprion polytomum, Htg.) in Eastern Canada led to a request to Farnham House Laboratory to investigate, and if possible collect and export, the parasites of this insect in its native home in Europe.Work started in 1932 and it was found that D. polytomum was a comparatively rare insect in Europe, though widely distributed. It is heavily parasitized, 31 species of Hymenopterous and Dipterous parasites having been found up to the present. Nearly twenty-eight million parasitized cocoons and eggs of this and other species of Diprion have been collected and despatched from Europe, and work is still continuing.Previous to the present work only 13 species of parasites, a list of which is given, were recorded from this host.Of the 31 species now known, 15 are primary, 5 can be primary or secondary, and 9 secondary only; in 2 cases the status is not known.Descriptions of all the species are given and in the case of the obligatory and facultative primaries, the biology and immature stages are also described and notes added on their suitability for introduction into Canada. A key to the adult parasites is given, and a key to the larval stages of the primary and facultative primary parasites. Some practical notes are also given, including methods of accelerating the emergence of parasites in winter and methods of preparing parasite larvae for examination and identification.

The most obvious effect of sleeping sickness is depopulation, which can be occasioned directly, through mortality from the disease, and indirectly, through a lowering of the reproductive rate of a community because of induced sterility and increased infant mortality.The problem was studied in the north of the Gold Coast and the neighbouring French Upper Volta Territory, where severe epidemics have occurred, in localised form since at least the middle of last century, and in widespread form during the past 30 years. The vectors have been the riverine tsetse Glossina palpalis and G.tachinoides.A close correlation was found to exist between the incidence of sleeping sickness and the population trend with a marked depopulating effect coming in at infection rates above 3 per cent. It was also found that both the rates of trypanosomiasis infection and the extent of depopulation showed closely similar relationships to the proximity of affected villages to the nearest flybelt.

From 1940 up to the time of writing, experiments have been carried out in the savanna country in the north of the Gold Coast on the trapping of Glossina palpalis and G. tachinoides, which are the most important vectors of sleeping sickness in West Africa.The habitat of these tsetse is described, with special reference to their feeding grounds, since those are the places where, trapping can be most effective and control of the flies is most desirable.A new type of trap, the Animal trap, was designed to meet the feeding habits of the two species of tsetse whose main hosts in the country where sleeping sickness is prevalent are man and domestic animals.The construction and maintenance of the Animal trap are described, the essential feature of which is a barrel-shaped body standing out well under good lighting and easily visible from all angles.Traps with a standardised 2-feet-long body raised 1 foot from the ground combined optimum catching with convenience in construction and portability.Light brown or khaki covering was slightly better than black, and rough material was decidedly better than smooth. Under poor lighting conditions these differences were less marked.Comparisons over long periods showed that the Animal trap caught over 20 times as many flies as the Harris trap which was not at all suitable for G. palpalis; about 10 times as many flies as Swynnerton's A.S.B. trap; and about seven times as many flies as Chorley's Crinoline trap.The correct siting of traps is of the greatest importance.Traps catch well anywhere in fly-belt but are most effective in open feeding grounds such as ferries, fords, waterholes and animals' drinking places.The regular presence of an abundance of hosts is the, most important single factor for good siting, and the nearer the traps can be placed to natural hosts the more effective they will prove.Traps should be placed if possible with their axes at right angles to the regular lines of movement of the flies.Good visibility of the trap from as wide an angle as possible is of great importance. Traps about five yards from the edge of the fly-belt catch twice as well as traps right at the margin of the bushes and considerably better than traps 40-50 yards out.Good lighting, especially from overhead, is an advantage but by no means essential.Good sites remain consistently good as long as the environment is unchanged, and bad sites remain bad.There is a tendency for the numbers of flies caught to fall by as much as 70 per cent, during the first few weeks when traps are placed in undisturbed fly-belt. This is the effect of skimming off a part of the fly population in the immediate vicinity of the traps and does not represent a real reduction in population.Comparison of tsetse catches by groups of five traps operating continuously, and by flyboys at the rate of 20 flyboy-days a month from parallel series of observations, gave the following facts for which explanations are offered.Traps relative to flyboys are more efficient in taking G. tachinoides and less efficient in the cases of G. palpalis and G. morsitans. Flyboys, however, catch a higher proportion of female G. tachinoides but a lower proportion of females of the other two species.It is considered that Animal traps represent the regular hosts of G. tachinoides and so attract non-feeding males as well as hungry flies of both sexes, whereas in the cases of G. palpalis and G. morsitans the traps represent something outside the range of their preferred hosts arid so attract only hungry flies bent on obtaining a meal.Traps appear to have a greater efficiency relative to flyboys in groves and clearings where the numbers of flies are small, than in sites in or near heavy and extensive fly-belt with high fly populations. This is possibly the result of competition which would be most evident in small tsetse populations and which would act in favour of the continuously present traps.There is a striking difference in the annual rhythms of catches by flyboys and by traps; the former showing a double-peaked curve with maxima at the beginning and in the middle of the wet season, the latter with a single peak towards the end of the dry season and a minimum during the rains.The efficiency of traps relative to flyboys is greatest in January and least in September. In an estimate based on all the available data and comparing 150 trap-days with 20 flyboy-days monthly, the traps at their best were 10 times as good as the flyboys, and at their other extreme were as low as one-fourth of the flyboys' catches.It is considered that this maximum efficiency in the dry season is not due to the flies' attraction to shade but that it is a complex result of the circumstances which bring about optimum conditions for trapping in the dry season, when the weather frequently puts flyboys at a disadvantage, and the most adverse conditions for trapping in the wet season when they enjoy certain advantages of mobility.The seasonal rhythm of trap catches has demonstrated the presence of a considerably greater fly population in the height of the dry season than is suggested by the magnitude of boys' catches.Three possibilities of trapping in the control of sleeping sickness are examined : (1) for extermination of the tsetse; (2) for reduction of the fly population; (3) for destruction of feeding flies in contact with people.Regarding the first possibility it had been found that continuous catching by teams of four flyboys could eliminate G. palpalis and G. tachinoides from small groves after 8–12 weeks' continuous catching but that, since none of these groves was completely isolated, repopulation took place by immigration, especially in the wet season. Small numbers of traps, 5–7 to the acre, made no apparent difference to limited tsetse populations but concentrations of traps up to 20 to the acre brought about considerable reductions and checked the effects of immigration, but with no approach to extermination of the flies.Eradication of the tsetse by traps is impossible but reduction of fly populations, if it can be effected over the main area of an epidemic, should, in theory, result in a partial control of trypanosomiasis.Small groups of traps well sited in feeding grounds bring about considerable reductions in the numbers of active, hungry flies in contact with their hosts although hardly affecting the main fly community. This, in theory, will have a definite protective value to the community, enhanced by the fact that traps show increased catching powers when in close proximity to man and animals and that there is a tendency for people and tsetse to concentrate around waterholes (thus coming into the most intimate contact), during the dry season, the very time when traps are working at maximum efficiency.It is in this protective role that traps seem to show their greatest possibilities for use in the control of sleeping sickness. The measure is applicable anywhere. It needs only small numbers of traps at each place where infection is being transmitted so that a reasonably big area could be covered economically. It might be a useful adjunct to clearings which fail to exclude the tsetse sufficiently. Traps so used might prove a valuable supplementary control-medium in places, such as the forest, where clearing is unlikely to be easy or cheap. Finally, experiment has shown that the retention of toxicity to Glossina of DDT-impregnated hessian exposed to the weather is sufficient to justify the application of DDT to the material covering the traps in order to increase their killing power.

A full description is given of the life-history of Exenterus abruptorius, Thb., an important parasite of the pine sawfly, Diprion sertifer, Geoff.The insect is univoltine, like the host. It oviposits on the last stage larva or prepupa and only hatches after the host has spun its cocoon. Only one-quarter of the primary larvae develop immediately, the remainder resting up to two and a-half months during the summer before proceeding with their development. On the completion of feeding the parasite larva spins its cocoon within the host cocoon and enters the prepupal stage, which can be divided into two distinct phases, eonymphal and pronymphal. Hibernation is always in the eonymphal stage. In Sweden 37 per cent. of this species remained in hibernation for two winters, but in Hungary all emerged in the spring following the year of development. Further than this, in Sweden the sexes were in approximately equal proportions; in Hungary females exceeded males by four to one. This may indicate the existence of biological races.Other Ichneumonidae exhibit the prepupal stage, with eonymphal and pronymphal phases, in their development. The typical facies of this is analogous to that in the prepupal stage in Tenthredinidae, in which, however, ecdysis precedes this stage, which is then a distinct instar. It is suggested that an instar is lost in the development of the Ichneumonidae, though the facies of the prepupal stage is retained.

This paper reports those findings concerning property management from the 1977-78 survey of tick control in Queensland, which could effect efficient tick control and also presents a profile of the cattle industry in the tick infested areas at the time of the survey. The average property size was 400 hectares and the average number of cattle on the properties was 726.4. Larger properties tended to have crossbred Zebu cattle. The average number of paddocks per property was 7.2. The most popular stabilised crossbred Zebu breed was Santa Gertrudis but the most common type of cattle was crossbred Zebu, which was on 30% of properties. There were negligible numbers of crossbreed Zebu cattle on dairy properties. Control of other external parasites may result in additional dippings in areas where they occur. Although fence maintenance appears to be carried out regularly it is clear that the effectivness of tick control measures, such as pasture spelling and dipping which depend on clean musters, could be affected by the occurrence of fire, floods and other natural disasters on half the properties in the tick infested areas. There is no evidence from results in the survey that attention to other farming activities (mainly cropping) prevents producers from paying sufficient attention to tick control. In fact cropping often provides the opportunity for producers to rotate cattle around pastures. Producers appear to consider the cost of tick control is a burden and they expect assistance from the Government to reduce these costs. They do not appear to have considered how they can reduce the costs themselves.

The economic benefit obtained from 2 schemes for the strategic control of helminthiasis in weaned lambs has been assessed in the Western District of Victoria. The results were compared with those from sheep in control groups which were given a single anthelmintic treatment during an outbreak of helminthosis. Mortality in sheep receiving the critical treatment scheme of 2 appropriately timed anthelmintic treatments was 12%, compared with 22% in the group receiving the traditional series of summer and autumn treatments, and 26% in the control group. As a result of this difference in mortality rate, the critical treatment scheme was the most profitable control strategy at 1970-71 prices, yielding a net benefit of $70 per 100 sheep in comparison with the control group which received no strategic treatment. This is 538% return on funds invested in anthelmintic treatment. The benefit from this scheme was not unduly affected by variation in wool or sheep prices, nor to possible differences in mortality rate within the expected range. The traditional treatment scheme also yielded positive net returns, but the results were adversely affected by a small change in mortality rate and therefore could not be recommended for routine use on commerical farms.

Information routinely supplied during the conduct of a dairy herd health program was analysed to evaluate the performance of artificial breeding in Victoria. A comparison was made between 60 to 90-day non-return rates (supplied by artificial breeding centres) and pregnancy rates (determined by manual pregnancy diagnosis) for first artificial inseminations in 108 herd years in which both items were available in the 1973 and 1974 breeding seasons. The values were 69.3% and 58.2% respectively (P less than 0.001). Non-return rates and conception rates were found to decline as herd size increased. Pregnancy rates to first artificial and natural services did not differ significantly from each other but pregnancy rates were significantly more variable to natural than artificial service (P less than 0.001). The mean pregnancy rate to artificial insemination for all herd years studied was 57.5% and the pregnancy rate to natural service was 58.0%.

SUMMARY A health program service was implemented on 9 farms, for periods ranging up to 7 years. Reproductive performance was substantially improved, when performance indicators were compared with values for the herds prior to commencement of the service. On average, the mean calving to conception intervals for the herds were reduced by 24 days over their periods of participation in the program, from an initial value of 119 days. The intercalving interval was reduced by an average of 27 days. This improvement was associated with a reduction in the mean dry period length of 20 days, from an initial value of 117 days. There was a tendency for the lactation lengths to be reduced to an undesirable extent due to slow adaptation by management to the improvement in reproductive performance, but the problem was corrected late in the study. The improvement in performance was attributed to improved oestrus detection, correction of temporary nutritional deficiencies, and prompt treatment of genital tract disorders in individual animals. Results for a range of performance indicators related to reproductive function are reported in detail.

The results of a survey on tick control carried out in 1977-78 indicate that tick resistant cattle have been introduced for their heat and drought tolerance and their ability to grow more rapidly than European cattle, especially in the extensive grazing country of Northern and Central Queensland. In South-eastern Queensland acceptance of tick resistant cattle has been slower because producers believe they are more difficult to manage than European cattle. A need for more publicity to be given to the different handling methods required by these animals was shown. Some producers cull their less resistant crossbred Zebu cattle and others could be encouraged to do so. Pasture spelling appears to be quite common especially in the Costal North; it is being carried out for pasture management rather than as a tick control measure. Producers in Central and South-eastern Queensland, who do not spell pastures, feel that it reduces the carrying capacity.

Survey results concerning chemical control of the cattle tick (Boophilus microplus) in Queensland are reported in detail, and differences due to region, breed and type of enterprise are discussed. The results show that chemical control was more intensive in Zebu and Zebu crossbred cattle than could be justified economically and that a minority of producers with European cattle carried out strategic dipping. Owners of plunge dips did not make regular use of testing facilities, available from the Department of Primary Industries or the chemical companies.