The failure of Boophilus microplus to be cleansed of Babesia bigemina while the ticks were growing on non-bovine hosts, as well as the infection of the non-bovine hosts, was demonstrated in experiments in which infected ticks were released on a number of sheep, a goat and a horse.

Seven of ten batches of ticks, collected from six non-bovine hosts, retained their babesia-infection.

Blood subinoculated into cattle from seven of nine sheep and from the horse showed that these animals carried B. bigemina whilst the ticks were feeding on them. This suggested that ticks may have become reinfected from the non-bovine hosts, a possibility supported by the finding of B. bigemina in blood smears from two of the sheep.

This work was performed at the Animal Research Institute, Yeerongpilly, and in the Department of Parasitology, University of Queensland, and supported by funds from both organizations. I am indebted to Mr G. D. Daly for technical assistance, to Professor J. F. A. Sprent and Dr H. M. D. Hoyte for their interest and help.

After penetrating through the body wall into the haemocoel of Bradysia paupera, the fertilized female of Tipius sciarae increased in size and slowly expelled the enlarging uterine cells through the vulva.

Within 7 days of penetration, the females were mature and began laying eggs into the haemocoel of the host. The eggs hatched in 3 days and, within 2 weeks, the host–s body was swarming with juvenile nematodes. The juveniles moulted three times in the body cavity of the host and 4th-stage forms emerged through ruptures in the intestine or body wall (in larval hosts) or were deposited on the surface of the soil (by adult female flies). They then moulted to adult forms while remaining ensheathed in their last juvenile cuticle, mated, and the fertilized infective females were ready to enter a new host.

Most parasitized fly larvae died before reaching the pupal stage but some emerged as adults, still carrying the nematodes within them. All parasitized adult flies were sterile. Infested larvae had smaller fat bodies and adult histoblasts than normal larvae and took twice as long to develop.

Preliminary tests suggested that this nematode may be useful in controlling sciarid gnats in glasshouses.

T. sciarae (Bovien) and T. gibbosus (Leuckart) were compared.

This work was done at Rothamsted Experimental Station, Harpenden, Herts, England, while the author held a postdoctoral grant from the National Institutes of Health, Bethesda, Maryland. I thank Mr F. G. W. Jones for a place in the Nematology Department, Dr Audrey Shepherd for supplying the New Blue R stain, Dr J. B. Goodey for advice, and Dr K. Lindhardt, Denmark, for the loaning of the late Dr Bovien–s slides of T. sciarae.

Pathological manifestations occasioned by mites of the genus Demodex are reported from Antechinus stuartii, a marsupial mouse. Derangements from single mite invasion of a hair follicle to massive nodule formation are detailed. In heavy infestations mites are found well distributed in the skin of the body with nodules limited, however, to the head, hind legs, around the base of the tail, the cloacal regions and, in females, just anterior to the pouch area.

Mites invade the hair follicle, where increase in their numbers leads to hypertrophy of the follicular epithelium which forms marked lobules surrounded by heavily vascularized connective tissue. It is thought that destruction of the lobule cells and penetration of the blood vessels due to increased mite numbers and activity leads to leucocytic infiltration with destruction of the mites and nodule deflation. In two instances of nodule deterioration a thickened skin plaque with markedly reduced mite populations remained in place of the nodule.

Gross symptoms of demodicidosis are occasionally marked in animals maintained in the laboratory but have not been found in specimens from the field. This suggests that environmental or dietary factors may be important in the onset of gross symptoms of demodicidosis.

This investigation was supported in part by a National Science Foundation (U.S.A.) grant (G-23321) and by a Commonwealth Scientific and an Industrial Research Organization (Australia) grant for marsupial research to the Zoology Department, A.N.U.

Dr Herman Beerman, Professor and Chairman, Department of Dermatology, Graduate School of Medicine, University of Pennsylvania, very kindly read and criticized our interpretation of the pathology. We are grateful for his help.

We would like to thank Margaret Dahlquist, Research Assistant, for her excellent technical assistance in the preparation of material for this report.

Three species of the genus Neoaplectana, nematodes from insects, when grown axenically, could be differentiated consistently by morphological, cultivational and serological criteria.

All three species were cultivated for consecutive generations on solid media such as a rabbit kidney slice at the bottom of an enriched agar slant. In axenic cultures with various liquid media, including some which were chemically defined, the ensheathed larvae of N. glaseri matured and produced offspring which in turn developed and reproduced; N. dutkii (‘DD-136’) larvae matured, but a new generation did not develop; the majority of N. carpocapsae larvae survived but did not mature. Living N. glaseri, used as a source of antigens to detect homologous antibodies, gave fewer cross-reactions than preparations of sonicated and frozen worms, and fewer false negative reactions than used cultivation media.

Morphological differences between the three species in cultures are described.

This work was done at The Rockefeller Institute in the department of Dr William Trager, with the technical assistance of June I. Schloemer and, subsequently, Kristin L. Schmidtchen. Preliminary morphological descriptions were made in association with M. B. H. Chitwood of the U.S. Department of Agriculture's Beltsville Parasitological Laboratory in Maryland. The author and work were supported by grants from the U.S. National Institutes of Health, 5-K3-AI-9522 and AI-04842.

Trichonema larvae are affected by light of visible wavelengths and there is a klinokinetic response to light intensity, the smallest rates of turning occurring in light of about 300 ft-c, and the rate of turning increasing with increased intensity (900 ft-c). In dim light the vertical migration of larval nematodes would be greatest, which explains in part the large recoveries from grass at dawn and dusk.

I thank Professor O. W. Richards, F.R.S., for permission to work at the Imperial College Field Station, and Professor B. G. Peters for help and advice. The work was financed by the Department of Scientific and Industrial Research.

Nosomma monstrosum was originally described from a male specimen under the name of Hyalomma monstrosum by Nuttall & Warburton (1908), and the female was described some ten years later by Warburton (1918). Three other males were also seen by him at this time, and he was somewhat hesitant to assign these ticks to the genus Hyalomma. The genus Nosomma was proposed by Schulze (1919) to accommodate this monotypic species, but this appears to have been done without seeing the species and his reasons for establishing the genus appear to be insufficient. Chodziesner (1924) and Sharif (1928) concur on the validity of the genus and the latter defines the genus as follows: ‘eyes flat, scutum, legs and dorsal surface of the capitulum ornate, festoons present, palps short and broad, basis rectangular dorsally in both sexes, coxae I bifid, other coxae with two short spurs on each, ventral shields in the male represented by adanal, accessory and trilobed subanal shields; spiracles short, comma-shaped in the male and subtriangular in the female’. Delpy (1936) agreed in the separation of Cosmiomma and Nosomma from Hyalomma, and in respect of Nosomma stated that ‘Caractérisé par des palpes dont l'article III est plus large que long et par des ecussons subanaux tres volumineux’. Generic status was also accepted by Toumanoff (1944) and Santos Dias (1954).

Pumping of the pharynx of Panagrellus has been shown to be a complex process involving three stages: the uptake of a number of globules by the corpus, the passage of the aggregate globule through the isthmus, and expulsion of the globule into the intestine by a number of pumps of the posterior bulb. It is suggested that Aplectana pumps in a similar manner to Panagrellus but at a faster rate. The pharynx of Rhabditis operated in two stages, involving the uptake of food first by the anterior half of the organ, and the subsequent passage of the ingested material through the isthmus and posterior bulb.

The pumping action of the posterior bulb suggests that the corrugated valves have a primarily valvular function. Regurgitation of intestinal contents through the pharynx is prevented by the internal pressure of the animals tending to force the walls of the organ together, and by the action of series of valves found throughout the lengths of the pharynges.

I should like to thank Professor J. E. Harris and Dr H. D. Crofton for their help during the course of this work, which was carried out during the tenure of a Postgraduate Studentship awarded by the Agricultural Research Council.

Ixodes arvicolae Warburton was collected at 2-monthly intervals from January 1961 to August 1962 on a total of 226 Apodemus sylvaticus and 264 Crocidura suaveolens cassiteridum in the Scilly Isles. Twenty-one adult females (out of a total forty-two ticks) were found on Apodemus and one adult female (out of a total 106 ticks) on Crocidura. No adult males were found. Ticks were collected from the hosts throughout the year, but in Crocidura there was a suggestion of greater frequency for larvae during the summer. I. arvicolae was also found on Mus musculus in the Scilly Isles and on Microtus agrestis in Cornwall.

We wish to thank Professor D. R. Arthur of King's College, University of London, for identification of the ticks involved in this study, and Dr Alec Milne of the University of Newcastle upon Tyne for helpful criticism of the manuscript.