bluuebunny/crossref_metadata_2025 huggingface dataset:
The susceptibility of tsetse flies to topical applications of insecticides. II.—Young adults of Glossina morsitans Westw. and organophosphorus compounds, pyrethrins and Sevin
Authors: Burnett G. F.
Published: July 2009

Solutions of six organophosphorus compounds, Sevin, and pyrethrins (alone or synergised with piperonyl butoxide) were applied by microburette in drops of constant volume (0·0216 μl.) to the dorsum of the thorax of young adults of Glossina morsitans Westw., 2–5 days old that had taken their first blood-meal the previous day. The solvents used were decalin (decahydronaphthalene), toluene and lighting kerosene, respectively.

Malathion, methyl-parathion, DDVP (dichlorvos) and Sevin were eliminated in preliminary tests as insufficiently toxic. Muscatox (coumaphos) was reasonably toxic but not readily soluble and was therefore not considered further. Diazinon and Baytex (fenthion) were fully evaluated; the former was about as lethal as DDT, the latter as γ BHC (LD50 about 0·004 μg.). The LD50 of diazinon for males (0·0115 μg.) was significantly smaller than that for females (0·016 μg.) but the LD95 was much the same for both sexes.

Pyrethrins were about equitoxic with dieldrin (LD50, 0·002 μLg.); when synergised with 15 parts of piperonyl butoxide to one of pyrethrins the LD50 for males was reduced to less than half this value, and there was a significant difference in susceptibility of the sexes, the LD50 for females being 1·4 times that for males. However, the slopes of the regression lines were such that at LD95 the difference between synergised and plain pyrethrins was too small to be of any practical use.

These results show that, judged by innate toxicity to young flies, none of these insecticides can compete with dieldrin or Telodrin for practical control, although Baytex is a useful reserve should Glossina acquire resistance to chlorinated hydrocarbons.
Locating the eggs of Aedes vexans (Mg.) (Diptera: Culicidae)
Authors: Lefkovitch L. P. , Brust R. A.
Published: July 2009

A procedure is described whereby, by the use of appropriate statistical methods, the approximate vertical distribution of the eggs of Aedes vexans (Mg.) in a pool can be ascertained from a relatively few samples taken without any previous knowlwdge of their position.
Variation in the size of insect parasites of puparia of Glossina spp.
Authors: Heaversedge R. C.
Published: July 2009

It has been found that the size of adults of the parasites Mutilla glossinae Turner and Thyridanthrax abruptus (Lw.) reared from puparia of Glossina differ with the size of the host, the puparia of the larger tsetse species, G. pallidipes Aust., producing larger parasite than the puparia of the smaller species, G. morsitans Westw. A significant relationship has been found between size of puparium (measured by puparial width) of G. morsitans and size of the parasite (measured by thoracic area and dry weight) for males of T. abruptus and males and females of M. glossinae, and it is suggested that this relationship may extend also to other species of Thyridanthrax and Mutilla that parasitise Glossina. Evidence, both from other workers and this laboratory, indicates that it is the different quantities of food supply in the hosts that affects the size of the adult parasite.
A jar for maintaining parasite-free insects and for collecting infected faeces
Authors: Harry Owen G.
Published: July 2009

Locusts and other Orthoptera have been reared free from Gregarine parasites in culture jars made from jam jars. Food can be added easily without the escape of insects. A special feature of the jars is the removable base in which faeces accumulate and from which they can be taken at intervals without exposing the insects to the infective stages of Gregarine parasites.
Descriptions of some new Species and some new Records of Coccidae.—I. Diaspidinae
Authors: Green E. E. , Laing F.
Published: July 2009

Puparium of ♀ dark-greyish ochraceous, narrow in front, broadening moderately posteriorly, straight or slightly curved.
Entomological Notes from Taranto (Italy) with References to Faenza, during 1917 and 1918
Authors: Hargreaves E.
Published: July 2009

These notes record some observations that were made during the anti-malarial campaign carried out by the British Army at Cimino, Taranto.
An inexpensive cabinet for temperature and humidity control
Authors: Carter C. I.
Published: July 2009

Details are given of a cabinet, with a working space of 9 cu. ft., affording temperatures constant to within ± 0·5°C. over the range 5–25°C. and relative humidities constant to within ±2·5 per cent, over the range 40·85 per cent. The apparatus has electrically operated automatic controls. The only maintenance required is two-weekly renewal of the wet-bulb wicks and filling of the distilled-water reservoirs. Most of the construction was carried out in the laboratory. The cost of the cabinet and control equipment was approximately £170.
Culture of an organophosphorus-resistant strain ofBoophilus microplus(Can.) and an assessment of its resistance spectrum
Authors: Shaw R. D.
Published: July 2009

Field observations indicated that a strain ofBoophilus microplus(Can.) in the Rockhampton area in Queensland was resistant to an organophosphorus insecticide, dioxathion (applied as Delnav), which had previously controlled it successfully. Ticks of this strain were despatched to the Cooper Technical Bureau in England, where a culture was established and maintained under selective pressure from dioxathion.

The non-parasitic stages of the culture were maintained in an incubator under controlled conditions, and the parasitic stages on cattle in a tick rearing house designed for the purpose. Careful security precautions were taken to ensure that there was no dissemination of tick life outside the confines of the culture. The tick rearing house was provided with double doors, the inner ones of which were screened with copper gauze to prevent the possible transmission of anaplasmosis by biting flies.

The activities of 23 insecticides against larvae of this strain and larvae of a strain ofB. microplussusceptible to organophosphorus poisoning were compared. The test method was an immersion technique, usually employing the insecticide in the form of an emulsion. Mortality was assessed 17 hours after treatment. These comparisons indicated that the strain was resistant to the organophosphorus insecticides carbophenothion (62 ×), dioxathion (25 ×), diazinon (15 ×), parathion (10×) and a carbamate, carbaryl (38×). It is suggested that these resistances may be due to a specific mechanism effective against these compounds.

Nine other organophosphorus insecticides, one carbamate and rotenone were subject to low-order resistance by this strain significant at P ≤0·05. This was considered to be non-specific resistance.

Dioxathion had been in use for tick control on the property concerned for four years before resistance was demonstrated. The property is situated in an area where the tick season lasts for ten months. In other parts of the world, dioxathion has been in use againstBoophilusticks for seven years without the development of resistance to it. The length of time resistance has taken to develop suggests that the resistance mechanism is not the expression of a single dominant gene, as has been demonstrated for dieldrin-resistance.

The results suggest that resistance to one or more organophosphorus insecticides will not necessarily prevent the use of other members of this wide and diverse group for tick control. Several of the insecticides shown here to be subject to low-order non-specific resistance are known to be effective tick dips, and one of them, ethion, has been used with success against the resistant strain.

An interesting corollary of the results was that the organophosphorus thions showed greater activity than their corresponding oxons against the susceptible strain.
A trap for Phlebotomine sandflies attracted to rats
Authors: Disney R. H. L.
Published: July 2009

Details are given of a trap for Phlebotomine sandflies attracted to a small mammal placed in a cage incorporated in the trap. It was developed in British Honduras for the purpose of studying the sandflies attracted to proven or possible hosts of Leishmania, other than man. The results of initial tests carried out at Central Farm from November 1964 to February 1965 are reported. These provided evidence that the sandflies caught in the trap were attracted to the rodents used as bait, and did not enter by chance; unbaited traps caught virtually no flies. In traps baited with rodents known to be reservoir-hosts of Leishmania, the species caught in greatest numbers was Phlebotomus apicalis Floch & Abonnenc, and amongst those caught in smaller numbers were P. cruciatus Coq. (including P. diabolicus Hall) and P. deleoni Fairchild & Hertig; it is suggested that all three are possible vectors of leishmaniasis in British Honduras. The relative numbers of the sandfly species caught in the traps were very different from those caught on man in British Honduras and by direct catching on animals in Panama.
A comparative study of the coconut flat moth (Agonoxena argaula Meyr.) and its allies, including a new species (Lepidoptera, Agonoxenidae)
Authors: Bradley J. D.
Published: July 2009

Taxonomic characters of the adult, pupa and larva of the coconut flat moth, Agonoxena argaula Meyr., are compared with those of the three other known species comprising the family Agonoxenidae, and keys to the species are provided. One new species, A. phoenicia, is described from northern Queensland. The systematic position of the family and the generic status of the four species are discussed. Although differences of possible taxonomic importance have been noted, the species are considered sufficiently homogeneous to allow assignment to the single genus Agonoxena Meyr. Haemolytis miniana Meyr. is transferred to Agonoxena, and Haemolytis Meyr. is suppressed as a junior synonym.
Effects of DDT on oxygen consumption of Rhodnius prolixus Stål
Authors: Spiller D.
Published: July 2009

When fasting fifth-instar larvae of Rhodnius prolixus Stål were poisoned with a lethal dose of DDT, the rate of oxygen consumption increased from the onset of hyperactivity, reached a marked peak shortly after knockdown, and then declined. For some days after the peak the oxygen consumption was markedly in excess of that prior to poisoning with DDT. Eventually, the oxygen consumption fell below the pre-teatment value and continued at this low level for some days, although the insect was then undoubtedly dead and in one case had been bisected. There was no marked discontinuity in the declining phase of oxygen consumption and therefore there is no indication of when death occurred. It is concluded that the time of death in DDT-poisoned larvae of Rhodnius cannot be determined by measurements of oxygen consumption.

The total oxygen consumed from poisoning until death was always less than that consumed in the normal use of all metabolic reserves by the fasting insect, and these experiments do not support the hypothesis that death in DDT poisoning is due to total exhaustion of metabolic reserves. However, it is pointed out that, in Rhodnius, some of the metabolic reserves are contained in the undigested residue of the blood-meal and in the massive endocuticle and that there is no reason to think that either digestion of the remaining blood-meal or resorption of the endocuticle could be speeded up during DDT poisoning. Hence there is a strong possibility that, in DDT-killed Rhodnius, death is brought about by exhaustion of the available reserves.

The peak rate of oxygen consumption during poisoning was greatest in very recently fed larvae and decreased as the interval between moulting and DDT-treatment was increased. This suggests that knockdown occurs when the fuel demands of the DDT-induced activity exceed the rate at which the fuel can be mobilised from the metabolic reserves.
Relative persistence on vegetation in northern Nigeria of DDT deposits from two formulations
Authors: Riordan K.
Published: July 2009

The persistence of DDT deposits on vegetation in the Northern Guinea Savannah zone of Nigeria was studied by chemical analysis of leaf samples and by bioassay tests with teneral females of Glossina palpalis (R.-D.). Two formulations of DDT were used, one (A) made by mixing a 75 per cent, wettable powder with water to give a 5 per cent, suspension, the other (B) made by adding a household detergent to A at the rate of 3·8 g. per gal. suspension. They were applied to foliage by knapsack sprayer in August 1964, about the middle of the rainy season.

It was noted that the particles deposited from B were finer and more evenly distributed over the leaf surface than were those from A. Chemical analysis of leaf samples showed that the deposit from B was initially the higher. Both deposits declined greatly during the first six weeks after application, coinciding with the period of heaviest rainfall. Those from A and B reached 49·8 and 46·2 per cent., respectively, of their initial levels at the end of the second week, and 9·2 and 5·2 per cent, at the end of the sixth. From then to the end of the sixteenth week, when the observations ended, no further decline was observed. In the tests with G. palpalis, deposits from A and B caused mortalities of 60.3 and 66.8 per cent., respectively, in the fourth week and 79·4 and 82·8 in the fifth, no mortalities below the latter being subsequently observed up to the tenth week.

It is considered that rainfall was the main factor responsible for removing the deposits from foliage. After the end of the rainy period, losses of the deposits became negligible. Deposits from B at first declined faster than those from A. It is considered that this was due to the faster removal by rain of the smaller particles.

Heavily weathered deposits were highly toxic to G. palpalis under the test conditions, and it seems likely that under natural conditions of contact they would have exerted still greater toxicity.
The effects of rearing conditions on the immature stages and adults ofSpodoptera littoralis(Boisd.)
Authors: Rivnay E. , Meisner J.
Published: July 2009

Some effects on the adult of environmental conditions during the larval and pupal stages ofSpodoptera littoralis(Boisd.) were investigated in the laboratory in Israel. The conditions studied were temperature during larval life, temperature and humidity during pupal life and the density at which larvae were kept, and their effects were found by varying one of them at a time. Except for such variations, larvae were reared in batches of 30–50 at 22–24°C. and 60–70 per cent, relative humidity, pupae were kept at 23–24°C. and 70–80 per cent, relative humidity, and adults were kept in pairs at 20–21 °C. and 75–85 per cent, relative humidity. Larvae were fed on clover leaves and adults on sugar solution.

High temperature during the larval stage reduced fecundity; whereas at 22°C. the resultant females laid about 1,200 eggs each and 12·5 per cent, produced non-viable ones only, at 30°C. they averaged about 700 eggs each and 50 per cent, produced non-viable ones only. Temperature during the pupal stage affected fecundity similarly and life-span to a lesser extent; at 20 and 34°C., 40 and 5 per cent, of the resultant adults lived 15 days or more, the percentages of females laying only non-viable eggs were nil and 70 and the mean numbers of eggs laid were about 1650 and 700, of which about 60 and 2 per cent, were viable, respectively. High temperatures were directly inimical to pupae, less than half of which survived at 26°C. or over.

The effects of humidity during the pupal stage were in general less than those of temperature. The mean life-span was longest in adults from pupae kept at an intermediate humidity of 76 per cent., as also were the proportion of barren females and the mean number of eggs laid; the percentage of viable eggs was reduced only amongst those from females kept as pupae at over 95 per cent, relative humidity. Pupal mortality was affected only by low relative humidities, which raised it.

Larvae reared singly tended to be brighter in colour than those reared in batches of 30–50; fewer died and the subsequent pupae were heavier and longer. The mean life-span of the resultant adults was longer, and they laid more eggs.

The results are compared with those of other workers onS. littoralisand other insects.
The distribution of Empoasca lybica (de Berg.) (Hemiptera, Cicadellidae) on cotton in the Sudan
Authors: Evans D. E.
Published: July 2009

The distribution on cotton plants of the eggs, nymphs and to a lesser extent the adults of Empoasca lybica (de Berg.) was studied on the varieties Bar XL1 and BAJ 7/57 in the Sudan during 1961–64. Counts of jassid nymphs in the process of hatching from eggs buried in the leaf veins showed that hatchlings were most numerous on the third to fifth expanded leaves from the main-stem apex and that most eggs had been laid either close to the point of insertion of the petiole into the leaf lamina or about half-way along the length of the veins on the underside of the leaves. The greatest number of hatchlings was found in the central leaf vein. It was concluded that eggs are most frequently laid in this position on newly expanded leaves at the apices of the main stems or side branches.

The distribution of the early instars on the main-stem leaves was peaked, with maximum numbers occuring on or about the fifth expanded leaf from the apex; a similar distribution with a less prominent peak nearer to the apex leaf was found on side branches. The later instars, being more mobile, had a more even distribution. In the over-all distribution of nymphs on a typical cotton plant, a combination of the patterns found on main-stem and side-branch leaves, the greatest numbers of jassids occurred in the upper half or upper third of the plant. Co-variance analyses showed that the relation between numbers of jassids per zone and number of leaves per zone was not close and that the manner in which the plants were divided into zones for analysis of the relation greatly affected the correlation coefficients obtained.

Regular counts of nymphs and adults on the upper surface of leaves throughout a period of two complete days showed that both nymphs and adults moved to the upper surface of leaves each day between 1400 and 1800 hr. local time and returned to the under surface at about 0300–0400 hr. Neither the environmental factor that stimulated this movement nor the way in which it benefited the insect was clear.
New evidence on the migration of moths of the African armyworm, Spodoptera exempta (Wlk.) (Lepidoptera, Noctuidae)
Authors: Brown E. S. , Swaine G.
Published: July 2009

Fresh evidence is described which supports the theory that moths of the Noctuid Spodoptera exempta (Wlk.) (the adult stage of the African armyworm) are migratory. The evidence comes from four main sources: a study of fluctuations in numbers of moths caught in a network of light-traps operated in East Africa; the fertilisation rates in samples of females as shown by dissection; the sex ratios in samples of moths caught in light-traps; and a study of the behaviour of moths in the field during the period immediately following emergence. In certain of these features S. exempta is compared and contrasted with the related S. triturata (Wlk.), in which the evidence points against extensive migration.

It is concluded that migration occurs in S. exempta, probably on an extensive scale, and that it therefore has an important bearing on the occurrence and distribution of outbreaks of the larvae.
The effect of feeding the tsetse fly Glossina Morsitans Westw. on impala blood
Authors: Langley P. A.
Published: July 2009

In a laboratory investigation in Rhodesia of the ability of Glossina morsitans Westw. to digest blood from the impala (Aepyceros melampus), the efficiency of digestion, as measured by the regression of the amount of haematin excreted in 48 hr. on the size of the blood meal, was found not to differ significantly between flies fed on impala blood and flies fed on blood from a variety of vertebrate hosts. This result, together with the report that captive flies can be induced to engorge from a live impala, refuts the suggestion that the low incidence of impala blood meals recorded in the firld is because impala blood contains a facor lethal to tsetse. One possible reason for the non-utilisation of this antelope, despite its abundance in tsetse areas, is its vigorous reaction to biting insects.
Biting cycles and parity of the mosquitoMansonia (Mansonioides) uniformis(Theo.) in Ceylon
Authors: Samarawickrema W. A.
Published: July 2009

Two series of all-night hourly catches ofMansonia (Mansonioides) uniformis(Theo.) on the verandah of a house and at an outdoor open site with man as bait and a third series at the same outdoor site with calf as bait were carried out during 1960–62 on an open mixed rubber and coconut estate overlooking a swamp, in Aggona, a village three miles south-east of Colombo. The physiological age of the mosquitos captured was determined by a count of the follicular relies in the ovarioles.

The mosquitos were active only at night; the biting cycle on human bait showed two peaks in both situations—a well-defined early peak and an irregular late peak on the verandah and a minor early peak and a larger lat peak at the outdoor site. In the verandah series the two oldest age-groups, 2-parous and 3-parous females, showed more activity during the second peak, while in the outdoor series the oldest age-groups were most active during the early peak, a result suggesting a difference in behaviour on the part of the older females compared with the overall population in both situations.M. uniformiswas strongly attracted to cattle bait; much activity was recorded at this bait site during the first four hours of the night.

Age-composition of the populations in all three series was found to be similar irrespective of the site and bait used. The results were more or less constant from month to month in spite of weather changes. Daily mortality ofM. uniformistaken at the two baits was similar and showed consistency from month to month.

A large proportion (73.4%) of females returned to feed directly from oviposition.
Anopheline mosquitos found breeding in Israel in 1963–1965 during the last stage of the malaria eradication project
Authors: Barkai A. , Saliternik Z.
Published: July 2009

Intensive surveys for breeding places of anopheline mosquitos have been carried out in Israel since 1948, and have proved to be very effective for following the dynamic changes in anopheline populations. An account is given is given of the situation with regard to the breeding of anopheline mosquitos in Israel between 1963 and 1965, in the final stage of the malaria eradication project. During this period only nine of the 14 species ofAnophelesrecorded in Israel were found, and of theseA. sergentii(Theo.) andA. superpictusGrassi were the most abundant.

About 85 per cent. of the breeding places were found in the northern part of the country. Fifty-four per cent. of the breeding places in the whole country were man-made. Seventeen per cent. of the 1330 samples of larvae determined contained larvae of more than one species. The distribution of different species in various biotopes and the seasonal variation in the number of breeding places of malaria-transmitting anophelines are also described.

A. sacharoviFavr., the most important malaria vector in the past, has not been found in Israel since 1960. The observations onA. sergentiisuggest that an exophilic strain of this species has been selected in Israel.A. coustaniLav., hitherto a rare species, has been found breeding more frequently in recent years.

The information collected during 1963–1965 is discussed for each species.
Productivity of Glossina austeni Newst. maintained on lop-eared rabbits
Authors: Jordan A. M. , Curtis C. F.
Published: July 2009

A life-table and age-specific fecundity schedule are given for females of Glossina austeni Newst. maintained on lop-eared rabbits. From these the innate capacity for increase in numbers (τm) is calculated, from two sets of data, as 0.0166 and 0.0155 per day, respectively. These values are better than previously obtained for Glossina and it is concluded that as such they were mainly due to the excellent nutrition of the flies. A colony in which all female offspring produced are added to the breeding stock is referred to as being in the ‘expanding phase’. The stable age distribution that would be established in a rabbit-fed colony of G. austeni in the expanding phase and the expected rate of increase in numbers of the colony when the stable age distribution exists are calculated from the value of τm.

The characteristics of a colony of G. austeni in the ‘stationary phase’, when only those offspring required to maintain the colony at a constant size are retained, are described. It is concludef that a stationary colony of y adult flies would have a disposable output per week of 0.277y young adult males and 0.233y young adult females. Some implications of these findings in relation to the sterible male techinque for tsetse control are briefly discussed.
Physical Factors in Mosquito Ecology
Authors: Senior-White Ronald
Published: July 2009

Over a quarter of a century has now elapsed since the genius of Ross convicted mosquitos of responsibility for the spread of malaria, but the factors involved in the distribution of the insects in Nature are hardly better understood to-day—when, in addition to filariasis and malaria, they have been inculpated in respect of the transmission of at least two other major diseases—than they were at the time of the original discovery of August 1897.
On some Tropical Copeognatha, especially from the Fiji Islands
Authors: Karny H. H
Published: July 2009

The present paper reports on a few Copeognatha received by the author for determination from the Imperial Bureau of Entomology, for which I am very much indebted to the kindness of the Director, Dr. Guy A. K. Marshall. Unfortunately all the specimens were dried and carded, so that it is impossible in some cases to give as full descriptions as are desirable for complete characterisation of the species, and as would have been done if there had been alcohol material at my disposal. Never-theless, it seems desirable to record all the species before me, as nothing has been known hitherto regarding the Copeognath fauna of the Fiji Islands.
Activity Cycles ofGlossina pallidipesAust.,G. palpalis fuscipesNewst. andG. brevipalpisNewst
Authors: Harley J. M. B.
Published: July 2009

A series of 24-hr catches ofGlossina pallidipesAust.,G. palpalis fuscipesNewst. andG. brevipalpisNewst. was carried out on the north-east shore of Lake Victoria over a period of 11 months in 1962–63. The object was to define and compare the daily pattern of activity of the three species as indicated by the numbers caught hourly on three black cattle that were used as bait. Catching during the hours of darkness was done by the light of dimmed hurricane lamps. The period of observation covered successively a dry season, a wet season, a cool dry season and a hot dry season.

At all seasons, males ofG. pallidipeswere caught in gradually increasing numbers from just before dawn until shortly before sunset, after which a rapid decrease took place. Females ofG. pallidipesexhibited a different pattern, with a gradual rise in activity in the morning until about midday, after which activity remained more or less constant until shortly before sunset, when a rapid fall occurred. There was never any indication of a morning peak in activity such as has been described for this species elsewhere. Activity during the night was at an extremely low level.

Activity of both males and females ofG. p. fuscipesstarted about dawn, increased to a peak in the middle hours of the day, and then fell fairly rapidly in the evening; the exact time of the peak was variable. None was caught during the night.

There was some activity ofG. brevipalpisthroughout the diel, but marked peaks of activity were exhibited by both sexes. In the open, these took place immediately after sunset and immediately before sunrise, the latter being the smaller. In the shade, the morning peak in both sexes was an hour later than in the open, and the evening peak in males alone was an hour earlier.

These results are compared with those of other workers, and the influence of physical factors is discussed. Particular values of temperature and saturation deficit were not closely associated with particular levels of activity of any of the three species, and light intensity is probably the physical factor that is most consistently the same at times of particular levels of activity at all seasons.
Effect of gamma-radiation on the tsetse fly Glossina Morsitans Westw
Authors: Dean G. J. , Wortham S. M.
Published: July 2009

Puparia of Glossina morsitans Westw. were collected in the Zambesi valley and contained developmental stages from final phases of third-instar larvae to pupae near to eclosion. These puparia or the emerging adults were exposed to gamma-radiation from a Co60 source at rates between 54 and 122 rad/min. Effective mortality in the pupal stage increased from 23 per cent, at 2,000 rads to 64 per cent, at 15,000 rads, while those deposited in spring (August-October) were more sensitive to gamma-rays than those collected in winter (May-July).

Under described test conditions, 25 pairs of untreated flies produced a mean of 21 pupae in a 28-day test period, insemination averaged 95 per cent., and 56 and 62 per cent, of the males and females survived, respectively. Continuous irradiation reduced reproduction by over 95 per cent, between 8,000 and 15,000 rads wiih males emerging within the first two weeks after treatment; while males emerging during the third post-treatment week were completely sterilised with dosages above 4,000 rads. Treatments given as fractions one and four days apart gave a slightly higher level of residual fertility than that obtained with similar but continuous total dosages. Irradiation of adult males reduced reproduction to an extent comparable with that observed in males emerging from pupae within two weeks of treatment (> 90 per cent, from 8,000 rads). Females treated either as adults or as pupae were completely sterilised with doses of 1,000 to 8,000 rads. Males exposed to 8,000 and 12,000 rads retained their sterility throughout 39- and 45-day test periods, and were fully competitive with untreated males.

Survival of virgin flies emerging from treated pupae was reduced both by increasing dosage from 4,000 to 15,000 rads, and decreasing pupal age at the time of treatment. Mortality during the 28-day mating period decreased with 1,000 and 2,000 rads, increased up to 8,000 rads, and apparently decreased with 12,000 and 15,000 rads. When the doses were fractionated, survival was longer than when treatment was continuous, and mortality was reduced to the level expected from the size of the first fraction. Virgin adult males given doses between 4,000 and 18,000 rads, and females given 2,000 and 4,000 rads, lived longer than the corresponding controls.

The ability of the males to inseminate females was not affected by any of the treatments, and sperm from irradiated males were mobile and apparently behaved normally. Dominant lethality in the males was expressed by the failure to produce pupae in matings with untreated females, and in the treated female fly by the complete failure of oogenesis.
Interplant movement of apterous aphids with special reference to Myzus persicae (Sulz.) (Hem., Aphididae)
Authors: Ferrar P.
Published: July 2009

It is likely that under some conditions apterous aphids are significantly involved in the spread of plant viruses, most importantly by walking across soil from plant to plant. Various factors which affect their importance are considered in the paper.

Figures are given for the frequency of movement of apterae of Myzus persicae (Sulz.) under settled conditions; this was found to vary with the species of host-plant that the aphid was on.

Eourth-instar and adult apterae can walk proficiently on soil. The effect of soil condition on this is described. The walking speed of adult apterae on soil is 5.2 cm./min. at 18°C, and 1.2 cm./min. at 8.5°C. The walking speed of fourth-instar aphids on soil is 3.2 cm./min. at 18°C.

Experiments showed that walking aphids are well able to locate a new host-plant, and that the attraction is visual.

The significance of these observations is discussed, and it is concluded that apterae have a greater potential as virus vectors than has been generally realised.
Juvenile hormone activity of ethylfarnesoate dihydrochloride with the cotton stainerDysdercus cardinalisGerst
Authors: Bransby-Williams W. R.
Published: July 2009

Cotton stainers (Dysdercusspp.) are members of the family Pyrrhocoridae and many are pests of cotton throughout the tropics. Ten species are found in Africa (Pearson, 1958). Three of these have been established in colonies at Arusha, Tanzania. They areD. cardinalisGerst.,D. fasciatusSign. andD. nigrofasciatusStål.
Effects of a juvenile hormone analogue on growth and reproduction in the cotton stainer Dysdercus fasciatus Say
Authors: Critchley B. R. , Campion D. G.
Published: July 2009

Williams (1960) suggested the use of insect hormones as possible pest control agents. Hormones are internal secretions that regulate a wide variety of physiological processes especially those concerned with growth, development and egg maturation (Novék, 1966). Similar activity has been reported for a series of compounds related to insect hormones and known as juvenile hormone mimics or analogues (see reviews by Berkoff, 1969; El-Ibrashy, 1970; Ellis et al., 1970; Wigglesworth, 1970). This paper presents the results of a laboratory investigation using one such hormone analogue, methyl farnesoate dihydrochioride (DMF) prepared according to methods described by Law et al. (1966) and Romaňuk et al. (1967) when applied to the cotton stainer bug Dysdercus fasciatus Say.
Observations on changes in the female reproductive system of the wheat bulb flyLeptohylemyia coarctata(Fall.)
Authors: Jones Margaret G.
Published: July 2009

InLeptohylemyia coarctata(Fall.) the germarium cuts off oocytes which develop through the stages 00 and 0 and I-V, recognised in other Cyclorraphous flies, in 4–5 weeks. All eggs of one batch of the gonadotrophic cycle ripen at the same time. After oviposition, the split intima, the remains of the follicular epithelium, and the nurse cells slowly contract to form the follicular relic. Flies swept from winter wheat during June and July and caught in water traps in July and August showed all stages of egg development. In 1970, 24·7% of the females swept from the crop had completed the first, 4–7% the second and 0–4% the third gonadotrophic cycle. All the eggs were not laid at the same time. During later gonadotrophic cycles, some ovarioles were non-functional. Flies laid one or two batches of eggs, rarely three. In 1970, many flies were attacked and killed byE. muscae. Only one out of 115 newly emerged female wheat bulb flies presented with foods usually found in the crop or citrated blood contained mature eggs after 24–27 days in small cages. Those fed only on 0·1 M glucose survived but did not deposit yolk in the ovum; those provided only with yeast paste died. Honey dew from cereal aphids was the main source of sugar. Water in droplet form and space to move seem necessary for the maturation of the eggs.
Notes on the genus Heterococcus Ferris (Coccoidea, Homoptera) with a description of a new species injurious to guineacorn (Sorghum Vulgare) in Nigeria.
Authors: Williams D. J.
Published: July 2009

The genus Heterococcus was erected by Ferris (1918) for a new species. H. arenae Ferris, having 9-segmented antennae, a denticle on the claw and with the normal trilocular pores replaced by quinquelocular pores. Other species were added later and Morrison (1945) discussed the genus at some length and described in detail three other related genera.
The effect of temperature, humidity and quantity of food on the development and diapause of Trogoderma parabile Beal.
Authors: Burges H. D.
Published: July 2009

The rate of development and the egg-production of the Dermestid beetle, Trogoderma parabile Beal, at 30°C. and 60 to 70 per cent. R.H. and the effect upon larval development of the volume of food, the temperature and the relative humidity have been determined.

In 15 to 450 cc. of wheatfeed at 30°C. and 60 to 70 per cent. E.H., active adults are formed from eggs in a mean of 39 days (egg 6, larva 26, pupa 5 and pre-emergence 2). Males develop slightly more rapidly than females. On average, a female adult lives 8 days and 53 of her offspring reach maturity. The weekly rate of increase of a population of stable age distribution (A) is × l·7.

At temperatures between 17·5 and 37·5°C. (and at 70 per cent. R.H.) and at humidities between near 0 and 90 per cent. R.H. (and 30°C.) larvae can grow to a large size; but in 0·7 to 25 cc. of food some of these large larvae enter a facultative diapause, as a result of restricted space. Disturbance of the food increases the proportion of diapause larvae. The diapause larvae feed and moult intermittently. At 30°C. and 60–70 per cent. R.H., a period of seven weeks after hatching has been adopted arbitrarily to distinguish diapause and non-diapause larvae. Only a limited success was obtained in breaking the diapause, which is less readily broken than that of T. granarium Everts.
Seasonal variations in the fat content and size of Glossina swynnertoni Austen.
Authors: Glasgow J. P. , Bursell E.
Published: July 2009

A population of Glossina swynnertoni Aust., at Shinyanga, Tanganyika, has been studied in respect of size and fat content of non-teneral males by monthly samples over a period of 13 years.

Flies are large from February to July and small from August to January, and this change in size suggests an effect of the wet season (December to May) and dry season (June to November) upon the parent females, allowing for the time-lag of two months representing pupal development and mean age of adult males at capture. Male flies have more fat in the rains and less in the dry season and it is possible that similar changes in the nutritional status of females are responsible for the observed size changes.

The correlation found in earlier work between the size of male flies in any month and saturation deficit two months earlier is confirmed, but reasons are given for rejecting a simple causal interpretation of this correlation.

Since 1951, there has been a progressive decrease in size of G. swynnertoni in the area studied, more especially as regards those produced in the dry season.
Rearing Pseudotheraptus wayi Brown (Coreidae) a pest of coconuts in East Africa, and evaluation of its susceptibility to various insecticides.
Authors: Wheatley P. E.
Published: July 2009

A method is described for the large-scale rearing of Pseudotheraptus wayi Brown, the Coreid causing immature nutfall of coconuts in East Africa.

Adults were kept in cages with sides of thick white drill and wire-gauze, in an outdoor insectary at Matuga, near Mombasa, Kenya, and were provided with freshly collected fallen nutlets from which the bracts had been removed. Eggs were normally laid on the walls of the cage. The nutlets were replaced every two days, and all newly hatched nymphs removed and placed in other cages supplied with fresh nutlets every second day. There was some mortality in the first- and second-instar nymphs due to the handling entailed when nutlets were replaced, but in the later nymphal stages it was very low. Under these rearing conditions, the life-cycle from egg to adult was completed in from 35 to 40 days.

The toxicities to Pseudotheraptus of dieldrin, DDT, γ BHC, malathion and pyrethrins in a solvent were compared by topical application of measured-drop doses from an Agla micrometer syringe in a range of five concentrations (except for DDT, where eight concentrations were used). The mortality counts at 72 hr. were taken as the measure of toxicity.

Analysis of the log dosage/probit regression lines indicated that dieldrin was markedly more toxic than DDT to Pseudotheraptus, and that the toxicity to this insect of pyrethrins was of a very low order.

In a supplementary experiment to determine whether the addition of resin improved the toxicity of DDT when applied topically, batches of adults were treated with measured drops of a solution of p, p'DDT (0·5 per cent, for females, 0·25 per cent, for males) and others with the same concentrations of DDT to which coumarone indene resin at one-tenth of the DDT content had been added. The toxicity of the DDT was not enhanced.
Relative humidity in the breeding sites ofGlossina morsitansWestw. in northern Botswana
Authors: Atkinson P. R.
Published: July 2009

Humidity measurements in air spaces in the soil ofGlossina morsitansWestw. breeding sites during the hot-dry season in northern Bostwana proved that ground holes were significantly more humid than tree holes, fallen logs or leaves. Site humidity decreased between September and October but did not differ significantly between riverine and mopane woodlands. Pupal mortality data demonstrated an apparent advantage in the dry season shift of breeding to holes. The evidence is only circumstantial that humidity is involved in site selection.
The Growth-Changes and Structure of the Egg of the African Migratory Locust,Locusta migratoria migratorioides, R. & F. (Orthoptera, Acrididae)
Authors: Roonwal Mithan Lal
Published: July 2009

The eggs ofLocusta migratoria migratorioides, R. & F., increase in size during development. The increase is due to the absorption of water from the surrounding moist soil.

The wet weight of a freshly laid egg is 0·0063±0·0008 gms, and of a fully developed egg 0·014±0·002 gms. The dry weight of a freshly laid egg is 0·003± 0·0004 gms. and of a fully developed egg 0·0024±0·0002 gms. The water-content of an egg increases from 51·92±3·53 per cent, of the wet weight in the freshly laid egg to 82·36±2·14 per cent, in the fully developed egg.

The egg-wall consists of an exo- and endochorion and a thick vitelline membrane. The latter has a felt-like structure in the freshly laid egg, but as the egg develops, this membrane increases in thickness and acquires a laminated character.

The micropylar apparatus consists of a ring of about 35–43 oblique, funnelshaped canals arranged round the egg near its posterior end.
A Short Reconnaissance of Northern Darfur (Anglo-Egyptian Sudan) with Regard to Schistocerca gregaria, Forsk.
Authors: Maxwell-Darling R. C.
Published: July 2009

A short tour of northern Darfur was made by the author, on behalf of the Imperial Institute of Entomology, with the object of observing the solitary Schistocerca population, comparing it with that of northern Kordofan, and looking for any factors which might indicate the presence of potential outbreak centres of the desert locust.
Berlese's Fluid: Remarks upon its Preparation and use as a Mounting Medium
Authors: Swan D. C.
Published: July 2009

Berlese's fluid has been known to entomologists for many years as a medium for making microscope mounts of small Arthropods; it has not been widely used, for which its unreliable keeping quality is perhaps partly responsible. It was developed by the late Professor A. Berlese, chiefly as a mountant for mites; apparently he did not publish the formula.
The Food-cycle of Dysdercus fasciatus in Acacia Savannah in Northern Rhodesia
Authors: Bebbington A. G. , Allan W.
Published: July 2009

A study of the variations of the population of Dysdercus fasciatus on cotton and on its wild host-plants is described.

The most important host of D. fasciatus in the Acacia savannah of Northern Rhodesia is Thespesia rogersii, and it is shown that at certain times a general flighting of stainer takes place from this host-plant caused by food shortage or defoliation. Generally a period of food shortage occurs during the earlier months of the year owing to rotting of the old crop and extensive destruction of the early new crop by the larvae of a Cossid moth. This causes an early influx into cotton, which leads to the establishment of a large population in the field at a critical period in the development of the bolls. When the early crop is retained on the trees a continuously increasing food supply is provided, and this first movement does not take place. A second movement from Thespesia, which is largely due to defoliation, begins generally in June. It has been shown that a second influx into cotton coincides with this later movement from Thespesia. A late influx such as this is of little practical importance since the greater part of the crop is picked in May and June.

The observations recorded indicate clearly that the movement of D. fasciatus into cotton is not due to any attraction exercised by the crop but is caused by a forced movement of stainers from Thespesia rogersii.
A Device for the rapid Counting of large Numbers of small Insects
Authors: Milne P. S.
Published: July 2009

During a series of experiments at Rothamsted with the mechanical insect trap described by Williams & Milne (Bull. Ent. Res. 1935, 26, p. 543) it became necessary to make counts of large numbers of insects three or four times a day over periods of several weeks. The following is a description of a device which was designed to facilitate the handling of the insects and to increase the speed and accuracy of the counting.
Mineral Oils as Mosquito Larvicides.
Authors: Murray David R. P.
Published: July 2009

Oil has been used as a mosquito larvicide for about forty years, since L. O. Howard in 1892 first recommended its use, and a large literature has accumulated on the subject, but the physical and chemical properties which make an oil a suitable material for this work are very imperfectly understood. It is clear that the problem is one that can very favourably be studied in the laboratory, for it requires above all an answer to the question “How do larvae die under oil treatment?” which can only be answered by microscopic examination of the larvae.
A European canon of literature?
Authors: Fokkema Douwe
Published: July 2009

For various reasons, the canon of literary works to be read in school has been criticized in recent years. The status of the canon, both as a concept with hierarchical connotations and as a particular set of texts, has been affected by developments in literary scholarship as well as by political views and new educational goals. However, teaching literature without the regulative idea of a canon is not very satisfactory. If we wish to select a limited number of literary texts to be taught in secondary schools, some consensus would be necessary about the functions of literature as well as about didactic goals, which in turn are related to concepts of morality and political exigencies. For instance, one may decide to teach not only a national ‘great tradition’, but to introduce a European perspective by incorporating works from abroad into the curriculum, if necessary in translation. In view of the fact that Europe is a multicultural community, it is of long-term interest to guarantee the pluriformity of any school canon of literature.
Crystallinity in polymers: an historical view
Authors: Allen Geoffrey
Published: July 2009

We still have much to learn about the morphologies of natural and synthetic polymers crystallized in bulk. Nevertheless, conventional X-ray and thermodynamic studies of crystallinity in polymeric materials over the past 60 years have given us a clear picture of the concept of crystallinity and the molecular features which promote crystallinity in these substances. Apart from issues of chain connectivity, the science of conventional molecules proved adequate for the task!
Museums of natural history—do we need their collections in the time of molecular biology?
Authors: Mathiasson Sven
Published: July 2009

All over the world natural history museums act as storehouses. Billions of creatures are preserved. Most museum visitors never see these collections; they only meet the limited specimens presented in public exhibitions. Most people seem to know little about the value of these collections and how they are used. This article presents some aspects of natural history collections and their value in scientific and other contexts.