It is suggested that if the vapour of an insecticide is rapidly adsorbed by a substrate the rate of volatilisation of the molecules of insecticide particles lying on the substrate is greatly increased. This explains the rapid loss of effectiveness of wettable powders on some soils. After the insecticide has been sorbed it is concentrated at and near the treated surface but afterwards slowly diffuses inwards. This diffusion reduces recoveries of insecticides from surface scrapings.

DDT can be recovered quantitatively from Uganda mud blocks 12 months after sorption is complete. Therefore, on this mud at least, catalytic decomposition does not occur.

A test has been devised for measuring the sorptive capacities of soil samples for non-polar vapours. It indicates if a soil is highly active but those with lower or negligible activities do not give a good correlation.

A survey of 18 soils from different parts of the world suggests that rapid inactivation of an insecticide by sorption should be expected on any red lateritic soil. Generally, others are inert or show only low activity.

Attempts to reduce or abolish the sorptive powers of Uganda soil have not been successful and the only effective method known at present is to limewash the walls before spraying. Pretreatment with a size solution also stops sorption but, unlike limewashing, at the same time reduces the efficiency of a subsequently applied wettable powder.

Finally, work by various authors on the inactivation of insecticides on mud surfaces is reviewed.

Energy allocation strategies have been widely documented in insects and were formalized in the context of the reproduction process by the terms ‘capital breeder’ and ‘income breeder’. We propose here the extension of this framework to dispersal ability, with the concepts of ‘capital disperser’ and ‘income disperser’, and explore the trade-off in resource allocation between dispersal and reproduction. We hypothesized that flight capacity was sex-dependent, due to a trade-off in energy allocation between dispersal and egg production in females. We used Monochamus galloprovincialis as model organism, a long-lived beetle which is the European vector of the pine wood nematode. We estimated the flight capacity with a flight mill and used the number of mature eggs as a proxy for the investment in reproduction. We used the ratio between dry weights of the thorax and the abdomen to investigate the trade-off. The probability of flying increased with the adult weight at emergence, but was not dependent on insect age or sex. Flight distance increased with age in individuals but did not differ between sexes. It was also positively associated with energy allocation to thorax reserves, which increased with age. In females, the abdomen weight and the number of eggs also increase with age with no negative effect on flight capacity, indicating a lack of trade-off. This long-lived beetle has a complex strategy of energy allocation, being a ‘capital disperser’ in terms of flight ability, an ‘income disperser’ in terms of flight performance and an ‘income breeder’ in terms of egg production.

The lack of biological knowledge of many invasive species remains as one of the greatest impediments to their management. Here I detail targeted research into the biology of the yellow crazy ant Anoplolepis gracilipes within northern Australia and detail how such knowledge can be used to improve the management outcomes for this species. I quantified nest location and density in three habitats, worker activity over 24 h, infestation expansion rate, seasonal variation of worker abundance and the timing of production of sexuals. Nests were predominantly (up to 68%) located at the bases of large trees, indicating that search efforts should focus around tree bases. Nest density was one nest per 22, 7.1 and 6.3 m2 in the three habitats, respectively. These data form the baselines for quantifying treatment efficacy and set sampling densities for post-treatment assessments. Most (60%) nests were underground, predominantly (89%) occurring in an open area rather than underneath a rock or log. Some seasonality was evident for nests within leaf litter, with most (83%) occurring during the ‘wet season’ (October–March). Of the underground nests, most were shallow, with 44% being less than 10 cm deep, and 67% being less than 20 cm deep. Such nest location and density information serves many management purposes, for improving detection, mapping and post-treatment assessments, and also provided strong evidence that carbohydrate supply was a major driver of A. gracilipes populations. Just over half of the nests (56%) contained queens. Of the 62 underground nests containing queens, most queens (80%) were located at the deepest chamber. When queens were present, most often (38%) only one queen was present, the most being 16. Queen number per nest was the lowest in July and August just prior to the emergence of virgin queens in September, with queen numbers then remaining steadily high until April. Nothing is known for any ant species about how the queen number per nest/colony affects treatment efficacy, but further research would no doubt yield important breakthroughs for treating ants. Activity occurred predominantly nocturnally, ceasing during mid-day. These activity data determined the critical threshold above which work must be conducted to be considered reliable, and also suggests that treatments are best applied in the afternoon. Total brood production peaked in February and was the lowest around August and September. These abundance data form the baselines for quantifying treatment efficacy, and may have implications for treatment efficacy. Males were found every month, predominantly between August and November. Queen pupae were found in September. The reproductive timing of sexuals determines the treatment schedule. Targeted, site-specific research such as that described here should be an integral part of any eradication program for invasive species to design knowledge-based treatment protocols and determine assessment benchmarks.

Two Macrolophus species, M. melanotoma (=M. caliginosus) and M. pygmaeus, have been referred to as efficient predators of several key pests on vegetable crops in Europe. However, due to the great morphological similarity of these species, they have been confused, with important consequences for inoculative releases of these predators in greenhouses and for the conservation of their natural populations on greenhouse and outdoor crops. In this work, we developed tools to identify these morphologically very similar species. We first confirmed the specific status of two Macrolophus populations collected on their respective host plants (Dittrichia viscosa and tomato) through crossing experiments. Then, using multivariate morphometric analysis, we proposed a linear discriminant function that combines head measurements separating males from the two species without error. Finally, we designed specific primers for a mitochondrial DNA region that were able to distinguish field-collected Macrolophus individuals through conventional PCR. In conclusion, the tools developed in the present study will allow reliable identification of the Macrolophus species present in crops and in the native flora that are the source of populations that colonise them. They will also allow correct identification of mass reared Macrolophus to be introduced in greenhouse crops in inoculative releases.

During November and December 1969, larvae and adults of the Anopheles gambiae complex from the Kisumu area of Kenya were identified by cytogenetical methods as species A and B. There appeared to be no difference between their choice of larval habitats. Although adults of both species were common in village huts, species B comprised 80·6% of the exophilic population. Adults of both species caught from huts and out of doors had fed predominantly on bovids; the incidence of human feeds was below 40%. The impact of residual insecticidal house-spraying would depend on the relative sizes of the endophilic and exophilic populations of species B.

The biting activity of Culex (Melanoconion) portesi Senevet & Abonnenc and C. (M.) taeniopus D. & K. in a secondary seasonal marsh forest in Trinidad was studied by means of catches by six mouse-baited suction traps, and a single light-trap. The traps were cleared at hourly intervals between 17.00 h and 07.00 h on nights which approximated to the new, first quarter, full and last quarter phases of the moon. The catches were compared with illumination at canopy and ground level which was estimated by selenium photocells whose output was recorded on the continuous chart of a servo-potentiometer. Humidity, rainfall, temperature and cloud cover were also recorded. In the suction traps both species showed peaks of activity at evening and dawn twilight at new moon, although the dawn peak was not very pronounced with C. taeniopus, but this pattern was modified on other nights in a manner which was consistent with moon age. At full moon the evening and dawn peaks were replaced by increased activity during moonrise and the middle of the night. The light-traps failed to show the evening and dawn activity and did not always duplicate the baited traps during darkness. Two hypotheses based on either a permissive range of illumination or an underlying circadian rhythm are discussed; neither fully explains the observed biting activity. Although an association between moonlight and biting activity does exist, an understanding of its nature will require more experimental data.

The probing activities of the most important leafhopper vector of maize streak virus, Cicadulina mbila (Naudé) (Hemiptera: Cicadellidae) were studied on different host-plants. Host preference was determined by giving the insects a choice of six plants, Digitaria sanguinalis, Zea mays, Zea perennis, Paspalum conjugatum, Oryza sativa and Saccharum officinarum (all Gramineae). Cicadulina mbila showed a strong preference for D. sanguinalis. Histological examination of plant tissues for salivary sheaths was used to reveal the preferred tissue. Cicadulina mbila tended to ingest from the phloem of its preferred hosts, and switch to mesophyll or xylem tissue on less preferred hosts. The suitability of each host was assessed by measuring the weight gain and amount of honeydew produced on each host by newly emerged adult females. Both parameters were greatest on the preferred host. Probing behaviour was also monitored electronically by recording the different waveform patterns produced when insects were probing, ingesting or not probing on the selected hosts. Cicadulina mbila probed less frequently, ingested longer and spent less time in non-probing activities on its preferred host, D. sanguinalis, although these responses were similar on maize and sugarcane. Rice induced poor probing responses and altered behaviour. This interpretation of the waveforms was supported by histological examination. As maize streak virus (MSV) is not found in phloem sieve elements, prolonged ingestion from sieve cells would not account for efficient acquisition from maize, which would require ingestion from other types of cells. D. sanguinalis was the host in which most ingestion from the phloem occurred, but it is the poorest source of MSV.

The night resting sites of Glossina palpalis palpalis (R.-D.) were observed in a riverine swamp at Bara, Bauchi Emirate, northern Nigeria. The flies were marked with an ultra violet reflecting paint and released at dusk. They were detected with the aid of an ultra violet light beam. Most of the flies (72%) rest on leaves (50% on the upper sides) and on small twigs and creepers (20·2%). The average resting height was highest in the mid-rains (3·78 m), dropped in the late rains (2·95 m) and was lowest (1·52 m) in the dry season.

The resting site heights ranged from ground level up to 18 m. Females were found to rest slightly higher than males and when the moon shone both sexes had a tendency to perch higher. It was shown that the night resting behaviour of G. palpalis is favourable to the application of residual insecticide deposits from the air because most of the spray drops are deposited on leaves.

In the ecologically sensitive Sahel of West Africa, two major crop pests, Helicoverpa armigera (Hübner) and Heliocheilus albipunctella (de Joannis), are attacked by Cardiochiles variegatus Szépligeti and C. sahelensis sp. n., respectively. The twelve Cardiochiles species present in the Sahel are revised, and a key is given for their identification. Five of these species (C. calvus sp. n., C. coelofrons sp. n., C. exiguurus sp. n., C. nixoni sp. n. and C. sahelensis sp. n.) are described, and C. striatus Brues is made a synonym of C. punctatus Szépligeti. Host relationships of the genus worldwide are discussed and the host records, principally involving Pyralidae and Noctuidae, collated. The known biology is summarized from the literature on the North American species C. nigriceps Viereck, and a comprehensive bibliography on the genus is given.

Dans la région écologiquement difficile du Sahel de l'Afrique de l'Ouest, on a découvert que deux importantes variétés d'insectes nuisibles à la culture, Helicoverpa armigera (Hübner) et Heliocheilus albipunctella (de Joannis), sont attaquées respectivement par Cardiochiles variegatus Szépligeti et C. sahelensis sp. n. Les douze espèces de Cardiochiles qui se trouvent dans la région du Sahel sont réétudiés, et une clé est formulée afin de les identifier. Cinq de ces espèces (C. calvus sp. n., C. coelofrons sp. n., C. exiguurus sp. n., C. nixoni sp. n. et C. sahelensis sp. n.) sont décrites, et C. striatus Brues devient synonyme du C. punctatus Szépligeti. Les rapports universels de ces genres d'hôtes sont discutés ainsi que la comparaison des rapports d'observation, principalement en ce qui concerne les pyralides et les noctuides. La biologie actuelle est resumée de la littérature sur l'espèce C. nigriceps Viereck nord américain et une vaste bibliographie du genre est présentée.

Cow dung was found to be suitable for breeding M. domestica vicina.

The dependence of the duration of development on the temperature was investigated for all stages of development and could be suitably expressed by the formula of an equilateral hyperbola.

Adult longevity was studied under various conditions of temperature and humidity. The maximum length of life in captivity was found to be 106 days, the average being 20–30 days. As the temperature rises, longevity decreases. Above 20°C, life is longest at a relative humidity of 42–55 per cent., whereas below 20°C., a lower humidity (30–40 per cent. R.H.) is favourable.

Fertility was studied from the point of view of size of individual egg hatches and the frequency of oviposition.

The mean number of eggs deposited by a female fly per day of adult life does not depend on the duration of adult life and does not change considerably during life.

Tetrastichus hagenowii (Ratz.) and T. asthenogmus (Wtstn.) are parasitic in cockroach oothecae and may themselves be attacked by a species of Tetrastichus of the group of T. miser (Nees). In Bangalore in 1976–79, the primary parasites were reared from oothecae of Periplaneta americana (L.), P. australasiae (F.) and P. brunnea Burm., and laboratory colonies of them were established on oothecae of P. americana. The hyperparasite, reared from field-collected oothecae of Periplaneta spp., was bred in the laboratory on oothecae of P. americana containing larvae of T. hagenowü. The immature stages of the three species of parasites were compared and their biologies studied. The eggs of the three species can be differentiated on the basis of their shape as can the pupae, but the larvae of the two primary parasites are indistinguishable. The duration of the developmental stages of the three species overlapped but the hyperparasite had a slightly shorter pupal period. Host finding by the T. hagenowii female was investigated. The two primary parasites were similar in most of their biological attributes. However, T. asthenogmus was inherently superior to the Bangalore strain of T. hagenowii in having lower levels of female sterility and its greater preference for the oothecae of P. brunnea, the predominant species of cockroach in Bangalore. T. hagenowii proved to be more tolerent of low temperatures than T. asthenogmus. The hyperparasite had an advantage over the other two species in possessing longer life-span and synovigenic females, and individual females parasitised more oothecae in their life-span than the primary parasites; but it was unable to distinguish healthy oothecae from those containing larvae of the other two species until it had drilled into them.

The separation of the closely related predatory species Macrolophus melanotoma Costa (= M. caliginosus Wagner) and Macrolophus pygmaeus (Rambur) based exclusively on the different colour pattern of the first antennal segment (white central band in M. melanotoma and entirely black in M. pygmaeus) is rather precarious and their taxonomic status is still in doubt. In the present study their taxonomic status was evaluated by DNA confirmatory analysis and hybridization experiments between M. pygmaeus and a Macrolophus taxon, resembling M. melanotoma, with a first antennal segment entirely black or with a white central band collected from Dittrichia viscosa (L.) W. Greuter (Asteraceae) in southern Greece. Adult females from Dittrichia plants hybridized with males of M. pygmaeus and vice versa did not produce viable eggs. The Macrolophus species from Dittrichia irrespective of the first antennal segment coloration differed from M. pygmaeusin digestive patterns generated by AseI, XbaI, and MseI on 16S rRNA and in RAPD profiles produced by the primers OPA-18 and OPA-20. These results demonstrate that on Dittrichia plants there is a distinct dimorphic taxon, M. melanotoma, as it is the only species of the genus Macrolophus bearing a first antennal segment with a central white band. Given the limitation of the coloration pattern, the mtDNA genetic markers are the appropriate method for the identification of M. melanotomaand M. pygmaeus.

The paper describes the layout and analysis of a test of two types of insect light-trap, the Rothamsted and the Robinson, and two types of illumination. The layout consisted of four variations of the sequence of six nights X A B O D D (X being a night of no trapping and A-D the four traps) in each of four sites in a small woodland. At the end of a complete cycle of 24 nights there had been four nights without trapping; each trap had been an equal number of times in each site; and each trap had followed all four trap-types, and also no-trapping, an equal number of times. The complete cycle was repeated four times at intervals between May and September. All insects captured were sorted into orders and counted and each order was analysed separately. By analysis of variance (after transforming the numbers caught to a logarithmic scale) it was possible to show separately the effect of differences, (1) between nights, (2) between sites, (3) between types of trap, (4) between types of light, and, (5) between cycles, and also the effect (if any) of the previous night's trapping. It was found that ultra-violet light was more efficient for all orders than ordinary electric light, that the Robinson type of trap was more efficient for the larger Lepidoptera but much less efficient for the small Diptera, but that there was no regular effect of the previous night's trapping. The largest source of variation was the difference between nights: difference between locations was small.

Leptoconops becquaerti (Kieff.) is one of the most troublesome species of biting midge in Jamaica. The gonotrophic cycle in this insect was studied and is described. In this species a single blood-meal is sufficient for the development of the ovaries and the maturation of eggs.

The stages in follicle development and digestion of the blood-meal adopted for other blood-sucking Diptera have been applied to L. becquaerti with slight modifications. A high degree of gonotrophic harmony is present in this insect.

Fully fed females were kept at five temperatures, 68, 77, 85, 91 and 98°F., to determine the time taken for the ovarian follicles to reach Stage V of development (egg mature, chorion present). The times were approximately 98, 64, 36, 30 and 27 hours, respectively.

It was demonstrated that the number of ovarioles in L. becquaerti was proportional to the size of the individual (as measured by wing length). The average number of ovarioles in an insect of wing length 0.83 mm. (the mean wing length of the population sampled) was about 103.

The number of eggs matured was also proportional to wing length, and was also dependent upon the temperature at which the flies were kept. Thus at the standard wing length of 0·83 mm., the average numbers of eggs matured at the five chosen temperatures (68 to 98°F.) were 78, 85, 65, 61 and 60, respectively. Females that had matured eggs were induced to oviposit by the decapitation technique.

Females provided with a source of carbohydrate (honey) during egg maturation produced slightly more eggs on the average than those fed on blood alone. The comparable figures at 91°F. in the standard individual were 65 and 61, respectively. The probable rôle of supplementary carbohydrate feeding in nature is discussed.

At the five experimental temperatures the greatest number of eggs hatched on days 11, 7, 5, 4 and 4, respectively, after laying. Egg-batches used in these experiments were deposited by decapitated females, and may therefore have been laid somewhat before the usual time in nature. The percentage fertility varied between individual batches at all temperatures, but the over-all fertility was consistently high (70–75%) at the lower four temperatures, and very low (4%) at 98°F. This difference almost certainly resulted from high temperature in the latter instance. Fertility in egg-batches deposited naturally (without decapitation) was of the same order as that in batches deposited by headless females.

1. The moth—Cydia nigricana—whose larvae bore into the pods of developing peas and render most of the contained seeds unfit for human consumption is considered by some authorities to be one of the principal insect pests of agriculture in Canada. It is particularly destructive in the Maritime Provinces and British Columbia, while in Ontario it increased to such proportions that the farmers of that province had to give up growing mid-season peas altogether.

2. This state of affairs is attributed to the fact that the pea moth was accidentally introduced from Europe in 1893 without the insect parasites which attack and check it in its native home. At any rate no parasites have emerged from the representative collections of pea moth material made by the Canadian entomologists in the affected areas, while three species with a combined parasitism of up to 60 per cent. have been reared by the writer from cocoons of the moth in England. Furthermore, in Canada, where parasites of this particular pest are absent, 10–50 per cent. of the pea crop and sometimes as much as 75 per cent. or more, is said to be destroyed annually by the moth larvae, whereas in England, where they are present, the attack is usually comparatively slight.

3. The paper opens with a general account of the biology of the pea moth including systematic descriptions of the adult and developmental stages, and notes on the host-plants and distribution of the insect.

The feeding of the cacao thrips, Selenothrips rubrocinctus (Giard), on cashew, Anacardium occidentale, one of its host plants in Trinidad, West Indies, is considered in relation to the annual period of maximum population increase on this host and to the choice of feeding sites on individual leaves. On trees observed for three years, populations regularly increased during the dry season, from a low level in December and January to a peak in April or May, and then rapidly declined during the wet season. Even when thrips were most abundant, some trees were free from attack, and this could not be attributed to protective morphological features, to specific repellent substances in the leaf, or to chance. S. rubrocinctus was found to feed on leaves that were subjected to water-stress and to breed only on debilitated trees: the evidence suggested that the adequacy of its supply of nutrients depends on the induction of suitable metabolic conditions within the leaf by water-stress.

Both nymphs and adults normally feed on the lower, stomata-bearing surface of the leaf, but in a very humid atmosphere only a weak preference is shown for this surface and if, under natural conditions, it is exposed to insolation by inversion of the leaf, the insects migrate to the other surface. Since the thrips were shown to be indifferent to bodily posture, the observation suggests that their behaviour is governed primarily by avoidance of exposure to undue heat or dryness and only secondarily by the attractiveness of the stomata-bearing surface.

Leaves of cashew tend not to become infested while still immature, and become most heavily infested, if at all, soon after they have hardened. Breeding does not occur on senescent leaves. The positions of feeding thrips are almost random on leaves under abnormal water-stress, but otherwise conform to certain patterns that mainly develop in fixed sequence. On reversal of an undetached leaf and consequent transfer of thrips from one surface to the other, there is no appreciable change in their distribution pattern or the apparent acceptability of the substrate. Changes of pattern were readily induced by injury to the plant during a period of water-stress and less easily, or not at all, when water-stress was low. Injury of areas of the leaf by heat was followed by their colonisation by thrips, and partial severance of branches by increased attack on their leaves.

Leaves detached from uninfested trees invariably became acceptable for feeding within four hours. During this period, leaf water-content declined and the ratios of soluble-carbohydrate content and α-amino acids to fresh-leaf weight fell slightly and rose considerably, respectively. In the field, the latter ratio was invariably higher for infested than for uninfested leaf tissue, even on portions of the same leaf. If the nutrient value of leaf tissue is determined by the rate at which α-amino acids are extractable through a stylet puncture, the observed change in acceptability for feeding following plucking may be accounted for by the increase in α-amino-acid concentration. Feeding that is restricted on any one tree to the margins of local leaf injuries during prolonged high water-stress and totally absent when stress is low can be correlated with an α-amino-acid content in the living marginal tissue that is high or low, respectively. The ability of thrips to establish themselves and breed on leaves of a particular tree in the dry season and their failure to do so on leaves of the same tree in the wet season conforms with the greater or less amino-acid concentration occurring in the leaf at these respective times.

This paper is my report of a year's work on the sheep blowfly problem at the Farnham House Laboratory of the Imperial Institute of Entomology. The investigation had a two-fold aim. Its immediate object was the development of a satisfactory large-scale methodof rearing Alysia manducator, and practical results in the form of shipments of the parasite were required. Its ulterior purpose was the accumulation of exact quantitative data on the interaction of a parasite and its host.

The object of this paper is to supply a means to the worker in the field for determining the Simuliidae that he may collect, with reasonable accuracy, until such time as he can have them identified by a systematist. A key to the females is given, and Mr. A. W. J. Pomeroy's figures of male genitalia and pupal filaments are reproduced. In this connection the worker is urged not to depend solely on the key to the females, which could no doubt be greatly improved upon when more materialis available, but to make use of the figures of male genitalia and pupal filaments where possible.

Previous records and new data on infection rates in species of Glossina inhabiting southern Nigeria and the Southern Cameroons are presented, and the probable economic importance of each species is assessed.

The trypanosome infection rates were highest in those species of tsetse which fed largely on Bovidae.

The rarity of human trypanosomiasis in southern Nigeria and the Southern Cameroons is attributed largely to impersonal man/fly contact; under such conditions a low proportion of infected flies is to be expected. G. palpalis (R.-D.) is not an important vector of sleeping sickness, as it is in northern Nigeria. The incidence of infection in G. palpalis was generally very low; cases of bovine trypanosomiasis do occur in areas where G. palpalis is the only tsetse species present, but it is not considered to be an important vector.

Little information is available on G. tachinoides Westw. and G. caliginea Aust. in southern Nigeria; both have probably been at least partly responsible for some of the rare outbreaks of sleeping sickness reported from the south. G. tachinoides may be of some significance as a vector of animal trypanosomiasis.

The infection rate in G. longipalpis Wied. at the West African Institute for Trypanosomiasis Research Field Station at Ugbobigha was 21·5 per cent.; this species is believed to be of major economic importance because its presence must prevent the keeping of cattle in large areas of potential grazing.

At least 13 per cent, of examples of G. medicorum Aust., G. fusca (Wlk.) and G. nigrofusca Newst. were infected in the populations examined, and the first two species are considered to be of economic importance because they penetrate potential grazing areas.

G. pallicera Big., G. tabaniformis Westw. and G. haningtoni Newst. are confined to rain-forest and were found to be lightly infected; they are therefore not considered to be of economic importance, except possibly as a source of infection to cattle on trade routes.

No data are available for G. nashi Potts.

By means of sticky traps and a suction trap, it was demonstrated on a plot of sugar-cane at Kawanda Research Station, Uganda, that large numbers of crawlers of Aulacaspis tegalensis (Zhnt.) become airborne (up to 10/m3). The numbers increase with wind speed up to about 2·0 m/s and then remain constant, but are depressed by increasing humidity. In laboratory experiments, crawler survival was reduced by high temperatures (30°C) and low humidities (30% r.h.), but some individuals should survive the extreme conditions sometimes experienced if airborne from morning until evening. On hatching, crawlers move upwards and towards the light, but downwards in the dark; movement is inhibited by high humidity. These behaviour responses indicate hat the presence of crawlers in the air is not accidental but a dispersal mechanism. At Arusha Chini, an isolated sugar estate in Tanzania, sticky-trap catches downwind of a windbreak confirmed that airborne dispersal of crawlers is a major source of infestation. It is shown that air currents could have carried crawlers to Arusha Chini from a source on the Kenya coast, 260 km to the east.