The following is a description of a new species of Accacoeliid Trematode found in the intestine of a sun-fish (Orthagoriscus mola Bloch), caught by a fisherman in June, 1933, at Salcombe, Devon. The fish was examined by Mr J. W. Poulton of Downing College, Cambridge, to whom my thanks are due for bringing me the parasites for identification. In addition to the species described in this paper the host contained the following forms: on the skin, Tristoma molae and Lepeophtheirus nordmanni; in the intestine, Ancistrocephalus microcephalus.

The genus Onchocotyle was named by Diesing in 1850 with O. appendiculatum (Kuhn 1829) as type. Cerfontaine (1900) reviewed the history of the group and revised the genus. He named the subfamily Onchocotylinae, containing three genera: Squalonchocotyle, Acanthonchocotyle (subsequently regarded by Monticelli (1903) as a synonym of Onchocotyle) and Rajonchocotyle. He discarded the older generic name of Onchocotyle, and placed the group in the group in the family Octocotylidae. Poche (1925) placed it in the family Polystomatidae Gamble (1896). Fuhrmann (1931) lists the group in the suborder Polyopisthocotylinea, family Onchocotylidae.

Nuttall and Warburton (1911, pp. 105–13) give a detailed account of the systematic survey of the family Ixodidae and recognise nine genera in the family. They consider Aponomma Neumann as a subgenus of Amblyomma Koch, but I consider it a valid genus.

Many basic data relating to the ecology of ticks are known, thanks mainly to the studies of Hunter, Bishopp and others on North American ticks.

1. Anagrus atomus (L.) Hal. is a mymarid parasite of the eggs of Erythro-neura pallidifrons Edwards.

2. The parasite is parthenogenetic, at any rate for the greater part of the year.

3. Two larval stages are described.

4. More than one egg may be laid in a single host egg and these eggs may hatch, but only one of the Anagrus larvae reaches maturity.

5. The development of Anagrus atomus takes about sixteen days.

6. The species is multi-voltine.

The Piraeeba, or Pirá-aïba (Piraïba) as Goeldi spells it, is a large Siluroid (my largest specimen measured 135 cm. in length) which is locally plentiful in the Amazon and has been described by Goeldi (1902). Goeldi named this species Piratinga pirá-aïba and it is the modern Brachyplatystoma filamentosum (Lichtenstein). I am indebted top Mr J. R. Norman of the British Museum (Natural History) for the modern name.

Montgomery (1917) showed that Nairobi sheep disease was commonly transmitted by Rhipicephalus appendiculatus. In 1931 we confirmed Montgomery's findings and extended them considerably in respect of transmission by this species of tick. It was shown that infection of any instar would result in transmission by the next succeeding stage, which would then in the normal course lose its infection during the next moult. A female tick infected in this manner as an adult would pass infection through the eggs to the larvae of the next generation. Further it was demonstrated that the transmitting stage could be reinfected if the reaction of the host animal commenced before the infecting meal was completed, thus ensuring the carrying on of infetion for a further stage.

Of the ten species which have been referred to the genus Rhadinorhynchus four (pristis, horridus, tenuicornis and exilis) are considered valid members of that genus. Selkirki is considered a synonym of pristis. Katsuwonis is placed in a new genus, Nipporhynchus, and it is suggested that ornatus may possibly belong with it. Medius is transferred to the new genus Gorgorhynchus of which a new species, G. gibber, is made the type. Wheeleri and johni are both referred to the genus Aspersentis.

The unusual occurrence of an infestation of Fimbriaria fasciolaris in the proventriculus of a swan is recorded.

The worms were associated with the presence of bipolar staining bacteria and ulcer formation near the site of their attachment.

The faeces of five elands (Orias canna syn. Taurotragus oryx) from Ascania Nova (Ukraine) were examined after concentration by Darling's method. Coccidial oocysts were found in the faeces of one of the animals. The oocysts were 21–24μ in length and 15–19μ. in breadth, with an average size of 21·1×17·8 The largest measured 24×19μ and the smallest 21×15μ The shape-index was 1:0·71–0·85, with an average of 1:0·85.

The Genus Nycteribosca was established by Speiser in 1900 for the species which were formerly placed in the genus Raymondia, Strebla or Brachystarsina. This author described one new species and redescribed four others which were already known. Quite recently the number of the species of this genus has been increased to nine by Falcoz. In this paper I have added seven new species, and also give a redescription and figures of all the known species. I have not included N. diversa Frauenfeld in my key, but at the end of this paper there is a description of this fly based on that of Frauenfeld (1856), and a copy of his drawing of the wing. The drawing shows very clearly the branch of the second longitudinal vein. N. diversa appears to be a very doubtful species; it has never been recorded since its original description was written. Moreover, according to Kessel (1925), there is no branching of the second longitudinal vein (R 2+3.) in the family Streblidae.

The material upon which this paper is based was secured in May, 1930, from a specimen of Scopus umbretta bannermani C. H. B. Grant (Ciconiiformes) which had been shot by a native on the Buzi River in Mozambique, about 40 miles from the eastern border of the Melsetter District of Southern Rhodesia. Several hours elapsed before the bird was brought into camp and its skin prepared for museum purposes, and our parasitological examination of the specimen was carried out under some difficulty with failing light. No worms were found in the alimentary tract, but on removing the liver and teasing this organ apart about twenty trematodes were recovered. To the naked eye these appeared very similar to schistosomes and, accepting this as a tentative diagnosis, we assumed that the parasites had been loosened from an abode in the branches of the hepatic portal vein. Considerably later, when we sought to identify the formalin-preserved specimens, it became evident that we had chanced upon an infection with a species of “holostome” closely related if not identical with that atypical and obscurely known form, Holostomum serpens.

Sixteen species of mites belonging to nine different families were found on Mus musculus and Apodemus hebridensis and in the nests of the former. Of these, eleven species may be regarded as parasitic in habit, two species have previously been recorded in association with rodents and moles, and three species may be described as accidental visitors.

I wish to thank Mr Elton and Prof. Munro of the Imperial College for their help, and I am also greatly indebted to Dr Caiman and Dr Finnegan for allowing me to make use of the facilities afforded by the British Museum (Natural History).

Three specimens were examined, the type, female, and two paratypes, male, collected by Mr B. A. Lever, from a small bat in the Russell Islands, Solomon Islands. They were sent to me by Sir Guy A. K. Marshall, whom I wish to thank for allowing me to describe them.

1. Anautogenous English and autogenous Greek, Hungarian, Maltese and cross-bred strains of C. pipiens were infected with an Algerian and a German strain of P. relictum.

2. The different strains of C. pipiens behaved similarly as regards susceptibility and transmission towards the same strain of P. relictum.

3. The two strains of malaria differ in the infection rate produced in mosquitoes. The Algerian strain produces an infection rate of about 89 per cent., while that of the German strain is only about 43 per cent.

4. The difference in the infection rates of the two strains is not due merely to differences in the number of gametocytes formed.

5. In general C. pipiens fed on birds infected with the Algerian strain of malaria became more heavily infected than those fed on birds infected with the German strain.

6. C. pipiens were infected in some cases by feeding on birds with chronic infections of the Algerian strain of P. relictum, but not when fed on birds with chronic infections of the German strain.

7. No seasonal influence was found as regards the infection of C. pipiens by P. relictum.

8. The Algerian strain of malaria was successfully transmitted by English, Greek, Hungarian, Maltese and Greek-Hungarian strains of C. pipiens, and the German strain of malaria by English, Greek, Maltese and Greek-English strains of C. pipiens.

During the last few decades, a considerable amount of experimental works has been carried out on the relations of insects to their environment: in certain groups such studies have advanced to an extent which renders possible tentative efforts at accurate prediction of their activities and spread. Among the arachnids, however, the experimental study of ecological relationships has been almost entirely neglected, and this despite the fact that several species, especially among the mites and ticks, are of marked economic significance. Since 1892–3, when the researches of Smith and Kilborne on piroplasmosis in cattle were published, ticks have been proved to be vectors of numerous important diseases of man and animals in many parts of the world, and much knowledge of their bionomics has been gained through observations conducted in the field and in the laboratory. The ecology of ticks under precisely controlled conditions, however, provides a practically unexplored field.

The case described in this note is believed to be unique, for no similar record has been found after search of the relevant literature. The subject of myiasis has been carefully reviewed and abstracted by Huber (1899), Umaña (1915) and Bedford (1927), and no cogent references of more recent date have been discovered.

The many factors governing loss of water from the egg of Lucilia sericata are discussed, and this loss of water is shown to be the probable cause of mortality and failure to complete development at different combinations of temperature and humidity.

In 1931 a number of fleas was received from Mr Georg Stein, obtained in Dutch New Guinea. Among them were the three species described below. We are greatly indebted to Mr Stein for having made this collection.

1. Atebrin given during the incubation period delays the appearance of parasites in the blood of birds infected by direct blood inoculation with Plasmodium relictum.

2. If given to birds infected by the bites of mosquitoes it does not retard the appearance of parasites in the blood, when given either before, or after, the infective bites, but it has some action in diminishing the severity of the attack and the degree of splenic enlargement.

3. Parasites appear in the blood of birds, infected by sporozoites, actually during the course of atebrin treatment if this is prolonged beyond the normal incubation period.

4. When asexual parasites appear in the blood of mosquito-infected birds after atebrin treatment they are abnormal in appearance and devoid of pigment grains; gametocytes are rarely seen in the blood of such birds, but if present they have normal pigment granules.

5. Treatment with atebrin produces peculiar bodies in the blood cells of canaries.