In 1915 Dowden reported a suspected case of tsutsugamushi disease, or Japanese river fever, from the Federated Malay States. Twelve years later Fletcher and Field (1927) were able to examine a series of cases and established Allothrombium. This spelling is adopted by Oudemans. In the absence of definite evidence of the original derivation, it would appear, in the light of Opinion 34 of the Rules, that the original spelling should be preserved, and Trombicula is therefore used in this paper.

Kenya Colony offers a rich field for the study of ticks and tick-borne diseases. The natural conditions under which both ticks and the diseases exist range from those of the hot, low-lying coastal lands to the equable climate of the highlands culminating in the colder upland country and mountain slopes. The variety of conditions is also attributable to the extensive tracts of bush-covered country, the high plateaux with their scanty growth of vegetation, and to the forest-clad ridges and mountains.

The British species of Aëdes, A.(Finlaya) geniculatus, lays its eggs on the damp surfaces of tree-holes containing water; or, if the expanse of water in the hole be large, often directly upon the water surface.

1. Cephenomyia auribarbis Mg., a tachino-oestrid parasite of the red deer (Cervus elaphus L.), is distributed throughout the deer forests of Scotland. The adult is found on the wing during June and July.

2. The larva normally occurs attached to the walls of the nasal passages and pharynx, where it remains for 10 or 11 months. At maturity it drops to the ground and pupates beneath the surface. The adult emerges in 3–4 weeks.

3. In January, 1931, a larva of the early third instar was recovered from a stag shot at Blair Atholl, Perthshire. It was found in fat in the pelvic region and not in the nostril or pharynx as might have been expected.

4. It is suggested that the larva may have been swallowed by the host and bored its way through the wall of the gut into the peritoneal cavity, whence it had wandered to the pelvic region; or else that a first-stage larva had been accidentally deposited by a female on the hide and had bored through the body wall to the peritoneal cavity.

5. The adult female and the early third-stage larva are described and illustrated.

6. A comparison is made between the cephalo-pharyngeal apparatus of Cephenomyia auribarbis, Cephalomyia ovis, and Gastrophilus intestinalis. It is noted that the basilar sclerite of the first two species is provided with an accessory lateral appendage on each side. A greater surface is thus furnished for the attachment of the large depressor muscles of the buccal hooks. The larva thus securely holds its ground in the nasal cavities and pharynx, where the risks of summary ejection are always present. In G. intestinalis the accessory appendage is absent. The chances of the larva of this species losing its hold on the gastric mucous membrane of the host are very slight.

Previous work on the effect of temperature and humidity upon the survival of unfed fleas is criticised in respect of experimental technique. In the present investigation measures have been taken to eliminate as many variables as possible and the methods employed to this end are described.

In the experiments, 2027 Xenopsylla cheopis, 999 X. astia and 646 Ceratophyllus fasciatus were employed, all unfed and less than 24 hours old at the commencement of the different experiments. Records were kept individually so that a statistical measure of consistency could be made.

The following conclusions have been reached:

(1) Duration of life of unfed fleas is not influenced by sex.

(2) High temperatures and low humidities tend to shorten life; conversely, low temperatures and high humidities, with a possible optimum of about 90 per cent., tend to produce longer lives.

(3) Humidity is at its maximum efficiency in this respect at about 18° C.

(4) At 37° C. humidity ceases to have any effect upon the duration of life of unfed fleas, and the evidence suggests that there is also a low temperature at which humidity has no influence upon survival.

(5) There is no direct proportion between survival of unfed fleas and saturation deficiency of the atmosphere at any temperature.

Comparing the species, it was found that:

(1) Ceratophyllus fasciatus was the longest lived, at similar atmospheric conditions.

(2) Xenopsylla astia lived longer than X. cheopis at all humidities at 23° C.

This paper contains a report on a collection of parasitic protozoa from the blood of some vertebrate animals of Uganda.

Seven new species and a number of parasites recorded for new hosts are described. New observations on some known parasites are also recorded.

An account is given of the life history of the crocodile haemogregarine. It is shown that the schizogony of Hepatozoon pettiti (nomen novum for Haemogregarina pettiti) occurs in the liver of the crocodile, while the sporogony takes place in Glossina palpalis, its intermediate host.

A list of all the blood parasites found, together with their hosts, is given.

1. Entamoeba aulastomi and Hexamita sp. from Haemopis sanguisuga have been cultivated in inactivated horse-serum diluted 1 : 10 in 0·5 NaCl solution + solid sterile rice-starch, and upon an inspissated horse-serum slope covered with the liquid medium + sterile rice-starch. Cysts of E. aulastomi appeared on or after the 9th day from subcultivation, but cysts of Hexamita have not appeared in the cultures.

2. The amoeboid phase of E. aulastomi divides by a simple direct method, without the formation of a spindle. There is no equatorial plate. It was not possible to count the number of chromatin granules.

3. The mature cyst is quadrinucleate, though occasional octonucleate cysts are found. Chromatoids are present but are absorbed before hatching. A. large glycogen vacuole is present in the uninucleate cyst. The nucleus divides by the formation of a delicate spindle but no chromosomes were found.

4. E. aulastomi are not harmed by being kept at 2° C. but they die out in the 2nd subculture if kept at 30° C. and within 24 hours if kept at 37° C. The cysts also are killed at 37° C.

5. If treated with N/20 HCl all amoebae are killed in less than 10 min. but the cysts are unharmed.

In Bufo vulgaris there is a small flagellate similar to species described from insects and the Brazilian cavy. Such flagellates were formerly placed in the genus Monocercomonas but the generic name has been amended to Retortamonas Grassi 1879 by Wenyon (1926). The toad flagellate which I name R. rotunda n.sp. differs in structure from Monocercomonas bufonis Dobell 1909, which Grassé (1926) has removed to the genus Tetramastix Alexeieff 1916.

The cestode herein described was obtained from the intestine of a Schokari Sand Snake which died on 16. xii. 1929 at the Zoological Gardens, Giza, after being 6 months in captivity. The material (Museum No. 1717) was placed at my disposal by Prof. Khalil for study in the Department of Parasitology.

The accurate identification of cestodarian and cestodan helminths depends so much upon the correct interpretation of their internal morphological features that a rapid yet satisfactory routine technique in their preparation for microscopical examination is much to be desired. Not all workers publish their technical methods, and, among those who do, no two seem to be in agreement. Some of the collection and preservation methods, in particular, which are advocated, whilst admirable for museum specimens or histological study, are impracticable under the conditions of a field survey, where many host animals have to be quickly examined and rapidly accumulating specimens are preserved and studied by methods which will not strain unduly the limited facilities of a field laboratory or a small biological station.

Two distinct species have been ascribed to the genus Ityogonimus: I. lorum (Dujardin 1845) and I. talpae (Goeze 1782). The difference between these two species was pointed out by Dujardin in 1845. In the case of I. talpae the ventral sucker is about one-third the diameter of the oral sucker, and is situated behind the anterior termination of the yolk glands. In I. lorum the ventral sucker is larger than the oral and lies completely in front of the yolk glands. Dujardin named the former Distoma ocreatum and the latter I. lorum. Witenberg (1926), in further researches on the species, came to the conclusion that the first-named was identical with Distoma talpae of Goeze (1782), and as a result of his work there now exist two species of Ityogonimus occurring in the mole, namely I. talpae and I. lorum. The synonyms of I. talpae (Goeze 1782) between the dates of 1782 and 1910 are as follows: Distoma talpae (Goeze 1782), Cucullanus talpae Müller 1787, C. ocreatus Shrank 1873, Monostomum ocreatum Zeder 1800, Distoma ocreatum Duj. 1845, D. lorum Melnikow 1865, Dolichosomum lorum Looss 1900, Ityogonimus lorum Looss 1907, and I. lorum Gonder 1910.

The cercaria is liberated from an unbranched sporocyst by the birth-pore. It is spindle-shaped and possesses a bifid tail. It possesses two suckers, a long oesophagus and a forked gut. The excretory vesicle is Y-shaped with two furcal extensions from its stem. The cuticle is unarmed. There is no stylet or cystogenous organ.

There is no redia.

All stages in the development of the cercaria are found within the sporocyst.

The species of Oesophagostomum here described has been collected quite frequently from sheep and goats in certain parts of the colony, always accompanied by the commoner oesophagostome O. columbianum.

The study of Aptinothrips rufus made in 1930, in the vicinity of Edinburgh, revealed the presence of a nematode parasite in the insect which seemed worthy of investigation. Little is known of the parasites of Thysanoptera in general, and I can find no record of any parasite of Aptinothrips.

In a previous paper (1927) I have given a general account of Dipterous larvae and their parasites living in the wounds of a horse-chestnut tree standing on the Downing site, Cambridge. This tree contained two types of wounds: (1) a surface wound with sap exudation or slime-flux, and (2) a large hollow or reservoir filled with water.

In 1927 Keilin described the fauna of a rot-hole and a slime-flux in a horse-chestnut tree (Aesculus hippocastanum) standing on the Downing site, Cambridge. For several consecutive years prior to 1927 he took there the larvae of the mosquito Orthopodomyia pulchripalpis Rondani (described as 0. albionensis by MacGregor), this being only the second record for Britain. In 1926 the chestnut tree was cut down and the part of the trunk containing the rot-hole was placed standing on the ground close to the Molteno Institute on its south side. As the rot-hole, after a time, ceased to be water-tight, its bottom was cemented and the “reservoir” kept filled with water. (For further details see Keilin in this issue, p. 280.) Three to four weeks later larvae of Orthopodomyia were found in the reservoir. It was not clear how this recolonisation had taken place as no other breeding place was known in the vicinity.

Oral and subcutaneous administration of the compounds aminopropyl-aminostyrylmethoxyquinoline trihydrochloride and o-β-diethylaminoethyl harmol hydrochloride causes the appearance of peculiar bodies in the blood cells of canaries and mice.

The bodies are irregular in shape and size, stain intensely blue with Leish-man's and Giemsa's stains, and are most numerous in erythrocytes, but occur also in eosinophiles, leucocytes and reticulo-endothelial cells.

The bodies show no cytological structure, are not seen to undergo multiplication, and are not transmissible by blood inoculation.

They are apparently non-living inclusions in the blood cells caused by the action of these two chemical compounds.