During a survey of the helminth fauna of the domestic cat in the immediate vicinity of Foochow, Fukien Province, China, the junior author discovered paired roundworms in the vestibule of the middle ear of this host. These parasites were first found in 1932 and again in the spring and fall of 1933. There appears to be no seasonal infection. Of forty-eight animals sacrificed eleven (22·9 per cent.) were found to be infected.

In human schistosome infections there is always the possibility that a patient may harbour a preponderance of male parasites, or that female parasites may be absent or remain undeveloped for long periods of time. This possibility is not generally recognised, in spite of the fact that the above-mentioned conditions are frequent in experimental tests. And it is evident that, if such conditions do hold for man, the mere absence of eggs from the urine or faeces is of little avail in determining the presence of an infection or in estimating the effects of treatment. Since, further, the ova are not readily detected in faeces and slight infections of the urine are demonstrable only when the very last drops of urine are collected and centrifugalised, a less uncertain and laborious method of estimation is clearly desirable. The complement-fixation test is not entirely trustworthy, though a negative result and a normal blood count would prove useful evidence of successful treatment. It is suggested in this paper that the degree of eosinophilia may afford a reliable confirmatory test.

A single specimen of a blood fluke was obtained from the gills of an amberjack or coronado, Seriola lalandi Cuv. and Val., taken by the writer on November 30th, 1929, from the Atlantic Ocean off Miami, Florida. This fluke belongs to the family Aporocotylidae Odhner 1912, and is regarded as the type of a new genus.

1. Of 259 cockroaches (Periplaneta americana) collected at Manhattan, Kansas, 86·3 per cent. were infested with one or two species of oxyurids, Leidynema appendiculata and Hammerschmidtiella diesingi. The highest incidence was among the immature roaches, of which 94·2 per cent. were infested; next was in the adult females with 87·5 per cent. infested; and lastly among the mature males with 79·5 per cent. parasitised. The female roaches carried the heaviest infestations and the young Periplaneta americana the lightest.

2. Uninfested cockroaches were obtained by rearing the young from oöthecae.

3. Oxyurid eggs in moist chambers remained viable for at least two months. Eggs of all stages when exposed to direct strong artificial or natural light for 15 min. failed to continue development.

4. Fertilised eggs incubated at 37° C. in dilute Locke's solution develop to the active embryonated stage in 20–36 hours; in 4–7 days they develop to the resting embryonated stage.

5. Regardless of the media utilised eggs failed to hatch in vitro.

6. Feeding experiments proved that transmission is direct. Eggs in the resting embryonated stage are infective; those in the active embryonated stage do not appear to be infective.

The present paper deals with a collection of parasites from Malay, kindly sent to Prof. Keilin at the Molteno Institute by G. B. Purvis, F.R.C.V.S., to whom the writer wishes to express his appreciation of the painstaking and scientific way in which the collection was carried out. The specimens were all very carefully sorted and clearly labelled, and the majority extremely well preserved.

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.

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.

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.

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.

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.

It will be convenient at this point, before proceeding to a more general discussion of the findings, to summarize all the experiments recorded in the eight preceding subsections. Briefly the results are as follows:

(i) An attempt to infect a Macacus rhesus by feeding it with Trichomonas isolated from a monkey of the same species failed completely.

(ii) Four similar attempts to infect a Macacus sinicus with the same Trichomonas (from M. rhesus) were equally unsuccessful.

(iii) Two attempts to infect another M. sinicus by intra-intestinal inoculation with the same flagellate were likewise wholly negative.

(iv) One attempt to infect a man per os with the same strain of Trichomonas (from M. rhesus) did not succeed.

(v) A strain of Trichomonas from Man, when fed to a Macacus rhesus, produced no infection.

(vi) The same strain (T. hominis) fed to a Macacus sinicus likewise failed to infect.

(vii) A strain of Trichomonas from Macacus nemestrinus, however, when fed to M. rhesus, gave rise to a temporary infection lasting about a month.

(viii) This Trichomonas (from M. nemestrinus, after passage through M. rhesus) produced, nevertheless, a permanent infection—lasting 4½ years to date—when fed to a man.

(ix) The same strain of Trichomonas (from M. nemestrinus), after passage through M. rhesus and Man, when fed to a Macacus sinicus gave rise to an infection which endured for approximately 1½ months and then died out. But

(x) The very same Trichomonas (which was derived from M. nemestrinus, and which produced a temporary intestinal infection in M. rhesus and M. sinicus, and a permanent intestinal infection in Man) when introduced into the vagina of M. sinicus established itself enduringly as a typical “T. vaginalis.” The infection has now persisted for ome 3⅓ years.

(xi) The monkey (M. sinicus) in which a permanent vaginal infection with an intestinal Trichtomonas was established, has probably since reacquired no permanent intestinal infection—despite every natural opportunity for such reinfection.

(xii) No macaque suffered any harm whatsoever as a result of inoculation with any strain of Trichomonas–whether successful or unsuccessful.

(xiii) The one man successfully infected with Trichomonas (from M. nemestrinus) has likewise remained normal ever since.

Flagellates belonging to four genera, Trichomonas, Giardia, Chilomastix, and Retortamonas, have been found in the caecum and colic loops of the muskrat, Fiber (= Ondatra) zibethica.

A Retortamonas is described from the caecum of two laboratory guinea-pigs.

The main object of this paper is the description of the larva of a new species of Cecidomyid, found by me in January 1933 in two old beehives from Selehurst, Horsham, Sussex. The adult Cecidomyids, reared from these larvae, were submitted to Dr H. F. Barnes, who has found them to be a new species described by him under the name of Lestodiplosis alvei, in the paper which immediately follows.

Male. Length about 1·5 mm. Antennae slightly longer than head, thorax and abdomen: 2 + 12, basal enlargement of flagellar segments with regular ring of moderately long stout setae and one ring of circumfila, distal enlargement with two rings of circumfila and irregular ring of stout setae, loops of circumfila regular and moderately long, those on basal enlargement extending about one-third length of stem, distal ring on distal enlargement extending about two-thirds length of neck; 1st and 2nd flagellar segments fused; 3rd flagellar segment with stem about three times as long as broad, neck slightly longer, about three-and-a-half times as long as broad, distal end slightly darkened as on all flagellar segments; 10th flagellar segment with stem about four times as long as broad, neck slightly longer in proportion. Palpi quadriarticulate with few setae: proximal segment quadrate, 2nd just over three times as long as broad, 3rd about three times as long as broad, the same width as 2nd, distal segment about four times as long as broad, slightly narrower than two previous segments. Thorax brown. Wings hyaline; 3rd vein reaching margin at apex of wing. Legs hairy; claws moderately curved, simple; empodium slightly shorter than claws. Genitalia: basal clasp segment long narrow, small basal lobe prominent; distal clasp segment long narrow, darkened; dorsal lamella moderate length and breadth, distinctly longer than ventral lamella, deeply emarginate, each lobe rounded; ventral lamella comparatively short but broad; style long, moderately stout.