It is known that, in solutions of some organic solvents such as pyridine, chloroform, ethylene dichloride and acetone, rotenone changes by oxidation to various derivatives, giving the solution a characteristic yellow colour (Jones & Haller, 1931). There is an accompanying loss in toxicity. Now that various intermediate solvents for rotenone in oils are being studied, it becomes of interest to know the stability of rotenone in these solutions.

Vast populations of Meligethes heteropus Gerstaecker have recently been found on millet in Nigeria. The damage they cause is described and the previously unknown male is described and figured. The validity of characters previously used in the diagnosis of Meligethes is discussed.

The persistence, as assessed by biological and chemical methods, of field deposits on apples from two spray programmes, each of DDT, carbaryl or azinphos-methyl, was compared throughout eight weeks following the first application in an orchard in south-eastern England. Newly emerged larvae of the codling moth, Cydia pomonella (L.), were used to assess, in the laboratory, the biological activity of the deposits. The spray programmes studied were (1) two applications of conventional concentrations (i.e., 0·1 per cent, for DDT and for carbaryl, 0·04 per cent, for azinphos-methyl) three weeks apart and (2) three applications of half these concentrations at two-weekly intervals. DDT wettable powder, carbaryl and azinphos-methyl were compared in 1961, DDT emulsion, DDT wettable powder and carbaryl in 1963. Results of biological and chemical assessment of the deposits are presented graphically. Over-all, the performance of the three-application programmes was as satisfactory as that of the two-application programmes, although a smaller amount of chemical was used. The serious reduction in deposit caused by heavy rain shortly after the first application of DDT wettable powder and of carbaryl in 1961 is noted. In the absence of heavy rain, carbaryl was biologically the most persistent, but the best performances of the other chemicals were almost as good as that of carbaryl.

LD50 values of fresh deposits obtained by field spraying were shown to be similar to those obtained by laboratory dipping.

Comparison of the toxicity of fresh and weathered field deposits of similar magnitude indicated that the biologically available proportion of a DDT deposit from either formulation decreases as a result of weathering. This phenomenon was not found to occur with carbaryl and either not at all or to a much lesser extent with azinphos-methyl.

The deposits obtained in the comparison of the spray programmes were separated into their fresh and aged components, so that differences in the contribution to the final deposit provided by each application could be seen. With the very persistent DDT emulsion, only about half of the six-week deposits was composed of chemical from the final application, but, with the much less persistent carbaryl and azinphos methyl, the six-week deposits were almost entirely derived from the final application. By substitution in an equation to obtain the rates of decay of the deposits from the three-application programmes of all chemicals, it is shown that deposits from the second and third applications were, in all cases, more persistent than those from the first. Possible reasons for this difference are discussed.

The significance, in terms of field control, of the results for the larvicidal activity of the deposits from the different spray programmes is indicated. It is concluded that data on the LD90 of insecticidal deposits on apples, together with measurement of their persistence in the field, can be used to assess the probable field performance of codling-moth insecticides and to determine the most efficient means of employing them, although the deposit level that ensures 90 per cent, larval mortality in the field is higher than the LD90 determined in the laboratory.

Medical Officers and others interested in tropical sanitation often find great difficulty in rapidly identifying adult mosquitos. Four Anophelines have been found in the Zanzibar Protectorate, two of these being well-known malaria carriers. The identification of the two latter with the aid of a pocket lens is quite simple.

In 1925 a brief generalised account was given of the biology of Sacadodes pyralis, Dyar, a Noctuiid moth that appeared likely to prove to be a serious pest of cotton, should the cultivation of this crop be taken up on a large scale in Trinidad. Previously little attention appears to have been paid to the potential danger, which the writer considers to be very real.

Sacadodes is not only very closely allied to Diparopsis castanea, Hampson, the Sudan bollworm, but it is also remarkably similar to that insect both in the general facies of all stages (Plates xxi and xxii) and in its bionomics.

When engaged on some entomological research in the extreme north of New Zealand, Mr. J. G. Myers, of the Biological Laboratory, Wellington, was attacked by a large number of small biting flies, specimens of which he was kind enough to send me for study. I am much obliged to him for having thus given me the opportunity of making known a new biting species of Ceratopogoninae, and I have much pleasure in dedicating it to him.

So far no species of this family of Diptera have been described or recorded from the Samoan Islands. The acquisition of a species of Tabanus by Dr. P. A. Buxton and Mr. G. H. E. Hopkins is therefore of great interest.

The Tabanidae of the Pacific Islands undoubtedly form an eastward extension of the family from Papua through Melanesia to Fiji ; various species are known from the Solomons, New Hebrides, New Caledonia, the Loyalties and Fiji, but the family is unrecorded from Tonga or islands to the eastward of Samoa. The Tabanidae thus represent a Papuo-Melanesian element in the Polynesian fauna. It might be mentioned here that two species of Tabanus, T. sidneyensis and T. nigriventris, were described by Macquart from “ Sidney Island,” which has been supposed to be Sidney Island in the Phoenix group. This locality is certainly erroneous ; most of the Diptera described as coming from there are known now to be common Australian forms and these two species are in all probability also Australian. The only other species recorded from Polynesia proper is T. insularis, Walker, described from the Sandwich Islands ; this record is also certainly wrong, since the group is not known to occur in these islands, of which the fauna has been extensively collected.

Oviposition and host discrimination behaviour of unmated Anagyrus pseudococci(Girault), an endoparasitoid of the citrus mealybug Planococcus citri (Risso), were investigated in the laboratory. Female parasitoids were able to discriminate between parasitized hosts and healthy ones. The mean number of ovipositions was significantly higher in unparasitized than in parasitized hosts. Conspecific-superparasitism occurred more often than self-superparasitism. Changes in consecutive ovipositions over three hours by A. pseudococci suggested that egg load influenced the discrimination behaviour of the parasitoids, with females which had low egg loads mostly avoiding oviposition in already parasitized hosts at time intervals ranging from 0 h to 96 h, and distributing their eggs in the high quality (unparasitized) hosts. The parasitized hosts were rejected more commonly through antennal perception of external markers than during ovipositor probing which could have encountered internal markers but this relationship changed with increasing time after oviposition. The parasitoid‘s oviposition rate in unparasitized and conspecific-parasitized hosts varied at the different oviposition time intervals when the females had fewer eggs in the ovaries. Percentage emergence of parasitized offspring was not significantly influenced by whether they developed in single or superparasitized mealybugs. The significance of host discrimination by A. pseudococci is discussed.

The relative contributions of host plant, herbivore species and clone to variation in the interaction between cereal aphids and wheat were investigated using five clones each of three species, Rhopalosiphum padi (Linnaeus), Sitobion avenae (Fabricius) and Schizaphis graminum (Rondani), on seedlings of two cultivars of Triticum aestivum L. and one cultivar of Triticum durum Desf. More individuals and biomass of R. padi than of the other two species were produced on seedlings. The three wheat cultivars lost similar amounts of biomass as a result of infestation by aphids, with the amount lost depending on aphid species: S. avenae caused the lowest loss in biomass. Variation in aphid biomass production was due mostly to differences among aphid species (70%), less to the interaction between wheat type and aphid species (7%), and least to aphid clone (1%). The specific impact of the aphids on the plants ranged from 1.7 to 3.7 mg of plant biomass lost per mg of aphid biomass gained, being lowest for R. padi and highest for S. graminum. Variation in plant biomass lost to herbivory was due mostly to unknown sources of error (95%), probably phenotypic differences among individual seedlings, with 3% due to aphid species and none attributable to aphid clone. For these aphid–plant interactions, differences among aphid clones within species contributed little to variation in aphid and plant productivity; therefore, a small sample of clones was adequate for quantifying the interactions. Furthermore, one clone of each species maintained in the laboratory for about 200 parthenogenetic generations was indistinguishable from clones collected recently from the field.

Flight activity characteristics of Chortoicetes terminifera (Wlk.) were recorded in adults suspended on a simple flight balance in a wind tunnel. Ninety-one per cent, of flights by post-teneral (>5-day-old) insects lasted less than 60 s, and only 11% of adults flew for a full 20-min test period at 30°C. The flight capacity ranged from a few or many short flights to continuous flights. Females flew for a greater proportion of the time than males. Flight activity increased with food-deprivation, and only fully hardened (>9-day-old) insects flew continuously throughout a 45-min test period at 26–41°C. Gravid females also made long flights. The frequencies of flight durations by laboratory-reared insects were strikingly similar to the day flight of milling field populations in eastern Australia. Flight performance observations indicated that lift declines with time in flight, wing-beat frequency initially being 33·2 Hz in males and 30·0 Hz in females. The results are discussed in relation to field studies.

A breeding-place of Glossina pallidipes Aust., in evergreen shrubs of Craibia sp. on the Kiangine river, Makueni, Kenya, was studied by means of hand-searching for puparia in conjunction with records of rainfall and temperature. A fly-patrol was also operated. The country away from the river was thorn-scrub, with Acacia and Commiphora trees predominating.

Three sites, each of 200 sq. yards, divided into 50 squares, were marked out, and two of them were searched monthly and the third quarterly.

Site “ A ” was searched nearly every month between April 1949 and June 1952, and full puparia were nearly always found. Numbers varied very widely; and it was noted that few could be found in rainy seasons during the months of November to January and April to May, though 1950 was an abnormal year. A consistently large increase in numbers was observed in February, the hottest and driest month, and a rather less marked increase towards the end of the long dry season in September and October. Large numbers of full puparia also tended to coincide with times of low average minimum temperature.

The numbers of flies caught on the fly-patrol did not appear to bear any close relation to the numbers of full puparia discovered.

Testing for efficiency of searching by means of marked puparia showed that about 40 per cent. of puparia were recovered, so that results must be taken as relative.

Chickpeas (Cicer arietinum L.) belong to the Fabaceae family and are one of the most grown crops in the world and an important source of protein for humans. Spodoptera frugiperda (JE Smith) (Lepidoptera: Noctuidae) is a polyphagous pest that causes significant crop damage. The objective of this study was to examine antibiosis to S. frugiperda in chickpea genotypes. The following genotypes were studied: Jamu 96 and Blanco Sinaloa 92 (Mexico); Nacional 29 (Cuba); BG 1392 (Spain), and BRS Kalifa, BRS Cristalino, BRS Toro, Nacional 27, 004UP, 003UP, BRS Cícero, and BRS Aleppo (Brazil). The chickpea genotypes influenced the biological parameters of S. frugiperda, of which larval period, larval weight, and pupal period were most affected. Nacional 29 caused high mortality in the larval and pupal stages of S. frugiperda. The larvae on BRS Aleppo had the longest larval stage, lowest weight, and longest pupal stage. The genotypes Nacional 29, Nacional 27, and BRS Cícero showed antibiosis resistance to S. frugiperda. These genotypes could be used as a source of resistance to S. frugiperda in conjunction with other methods of pest control in integrated pest management programs for chickpea crops. These resistant genotypes could also be used as donor sources in breeding programs for insect resistance.

The larvae and pupae of Tryporyza innotata (Wlk.), T. incertulas (Wlk.), Chilo suppressalis (Wlk.), C. polychrysa (Meyr.) (Pyralidae) are described and notes are given on Sesamia ingerens (Wlk.) (Noctuidae) with particular reference to setal characters of the larvae. No obvious difference in chaetotaxy was found between T. incertulas and T. innotata, but the two species of Chilo could be distinguished on this basis. The pupae of the species of Tryporyza could be separated by differences in the shape of the labrum and those of the species of Chilo by differences in that of the thoracic tubercles.

The insecticidal Potencies of DDT, dieldrin, isobenzan, malathion, diazinon and arprocarb were assessed both by topical application of oil solutions to test insects any by exposing the latter to residues on glass, using young male and non-pregnant female adults of Glossina morsitans submorsitans Newst., G. austebi Newst., and Chrysomya putoria (Wied.).

By topical application, dieldrin and isobenzan were 10–23 times as potent as DDT, but their residues were on ly 2.2–6.3 times as effective; arprocarb was likewise more effective by topical application than as a residue, being, respectively, 9 and 3.5 times as effective as DDT. In contrast, diazinon, and, especially, malathion tended to be more efficient, relative to DDT, as residues than might be expected from application tests.

It is presumed that the difference between the ralative potency of an insecticide as a reesidue and as applied topically reflects the physical factors affecting contamination and penetration of the insect, but these matters have nor been stuided with tsetse flies.

Attempts were made to find alternative, less persistent, toxicants to aldrin for use in baits against Anoplolepis longipes (Jerd.) in the Seychelles. More than twenty toxicants were tested (some in more than one formulation) for effectiveness as poisons and for repellency to ants at the concentrations used in baits. None was as effective as aldrin, but certain formulations of pirimiphos-ethyl, pirimiphos-methyl and mecarbam were promising because they gave good kill of ants in the laboratory and were of relatively low repellency and therefore acceptable in bait formulations.

Pomello and lemon seedlings kept for different time periods in various nutrient solutions were examined for their degree of infestation with Aceria sheldoni (Ewing), the citrus bud mite. Chemical analyses indicated that seedling leaves and buds had a higher nitrogen content in a potassium-free solution, and a lower nitrogen content in a nitrogen-free solution, when compared with their respective contents in a standard solution; in buds these differences were also shown by certain amino acids. Infested seedlings kept in a potassium-free solution had significantly more mites than those kept in a nitrogen-free solution, and the latter had significantly fewer mites than those kept in a standard solution. No increase in mite populations was noted on seedlings kept in high-nitrogen solutions. The relationship between the levels of potassium, nitrogen, magnesium and manganese and the mite population is discussed. No effect on mite reproduction was noted when sodium or calcium was used as a substitute for potassium.

Au mois de mars de l'année 1933 j'ai accepté l'invitation de Monsieur E. Guest, Officier inspecteur de l'Agriculture en Iraq et en même temps Botaniste, de visiter l'Iraq pour lui aider dans quelques travaux qu'il voulait poursuivre, et le 30 mars j'ai quitté Jérusalem, accompagné par Monsieur Guest et par Monsieur M. Zohary, mon assistantet collaborateur. Arrivant à Baghdad les premiers jours d'avril, j'ai été invité par Monsieur le Ministre des Economies et des Communications et par le Directeur Général de l'Agriculture de faire cette visite au compte du Gouvernement Iraquien et de m'intéresser pendant mon tour spécialement aux problèmes de la botanique appliquée et particulièrement au problème des sauterelles et du reboisement et de l'afforestation. J'ai accepté volontiers cette invitation. Il me fallait prolonger le séjour en Iraq de dix jours de plus qu'il a été projeté d'abord. Ces dix jours étaient presque entièrement consacrés à l'étude de la végétation des champs de ponte des sauterelles.