Dr F. W. Edwards has kindly submitted to me the specimens of Streblidae collected by him in March 1935, during his entomological expedition to East Africa, in the caves near Kapretwa, at 6500 ft., on Mt Elgon, Kenya. To this material he added the specimens collected by Dr G. H. E. Hopkins, in the same locality, and asked me to write a short report.

Habitat and material. About a hundred specimens including both sexes were taken on the upper surface, especially the dorsal and ventral fins, of two Zeugopterus punctatus (Bloch), 13 and 21 cm. respectively in length, by Miss Nora G. Sproston at Roscoff in September 1938.

I am greatly indebted to Prof. O. Nybelin of Göteborg for the loan of two specimens of female Lernaeopoda scyllicola Leigh-Sharpe, 1915 taken by him from the extra-cloacal region of two Scylliorhinus canicula (L.) during the first fortnight of September 1938 at Roscoff which show peculiar cases of pigmentation (Fig. 1).

The life cycle of Coitocaecum anaspidis involves three important stages. The adult occurs in Galaxias brevipennis, G. attentuatus, Gobiomorphus gobioides, and in specimens of Anguilla spp. less than 30 cm. long. Potamopyrgus antipodum and P. badia are the molluscan hosts of the sporocyst and cercaria. In New Zealand the cercaria attacks and encysts in Paracalliope fluviatilis, and in Australia in Anaspides tasmaniae. A metamorphosis of the cercarial larva into a progenetic metacercaria takes place in the amphipod.

Paracalliope does not become infected with Coitocaecum till the crustacean has reached 2·0 mm. in length. The thigmotropism of the Paracalliope fits exactly with the ground-living habit of the stumpy-tailed cercaria. The small river fish feeding in slack water acquire Coitocaecum from Paracalliope.

Leishmania forms of L. tropica were obtained in cultures. The methods and results are given and discussed.

Previous workers have described the curious method by which the female bed-bug is fertilized. They have suggested that the large quantity of sperm injected serves some function other than that of fertilizing the egg.

The rate of metabolism of the virgin bug is much less than that of the fertilized female.

Ovarian development never occurs until the female has been fertilized. After fertilization, egg development is apparently controlled by a hormone produced by the corpus allatum.

Living sperm will always be found in the spermathecae of females which are laying fertile eggs.

The so-called imperfect eggs produced when the sperm is exhausted are normal save for being unfertilized. They have been considered as malformed because of their tendency to shrivel quickly in dry air.

Sperm remains viable in the female for a definite period depending on the temperature. This period is longer at low than at high temperature. Provided a certain minimum amount of sperm is introduced (this minimum is less than the quantity introduced by a well-nourished male at one copulation), the period of viability of sperm is the same no matter how many eggs are produced. The number of eggs depends only on the amount of food taken.

There is no evidence that the sperm serves any nutritive function in the female.

A natural infestation of bed-bugs which has existed for several years in an animal room has been studied. The bugs feed on the rats kept in cages in the room.

Methods are described by which the bugs were trapped during their periods of normal activity.

Adult bugs appear to feed on an average once every 5 or 6 days when the temperature is in the region of 20–27° C. (68–80·6° F.). Most of the female bugs lay a continuous series of eggs at the rate of nearly three per day.

Female bugs are not usually fertilized more than once a week in this wild population. In laboratory cultures copulation is much more frequent.

In the animal house the bugs were most active between 3 a.m. and 6 a.m. This activity seems to be controlled by some inherent rhythm.

Some marked bugs were released and the proportion of recaptures to others in the total catch was noted. From this a rough estimate of the population was made. It appears that few adults live more than 29 days as they are probably killed by the rats when trying to feed.

1. Vogel's (1920) assertion that the labral canal is closed ventrally by apposition of the edges of the labral groove is fully confirmed. The hypopharynx plays no part in the ventral closure of the food canal except at its base. The somewhat popular term “labrum-epipharynx” is dispensed with in favour of “labrum”.

2. The mandibular teeth vary in number round about 40. The mandibular suspension is fully described.

3. Evidence from musculature is put forward for the existence of a small maxillary palpifer not present in other Diptera.

4. Snodgrass (1935) criticizes Crampton's (1925) homologizing of the labella with labial palps because “the lobes of the fly labium have usually each only one muscle inserted directly upon it”, whereas palpi usually have antagonistic muscles. Vogel for Culex and this paper for Anopheles maculipennis show that the labial lobes of these insects have antagonistic muscles like typical palpi.

Examination of mite material sent from various sources for identification has revealed a number of new species. In this paper seven new species of Laelaptinae, one of Entonyssus and one of Listrophoroides are described.

In a recent paper Dr L. R. Cleveland (1938) has published some observations on a remarkable flagellate called “Teranympha”, which was discovered nearly 25 years ago by Dr M. Koidzumi in the white ants of Japan. I do not now propose to discuss this singular organism itself, however, but only its name and certain other matters of wider interest which its nomenclature suggests—matters which seem to me, indeed, to merit the immediate attention not only of all parasitologists but even of zoologists generally.

1. The mosquito fauna of the Cambridge district, which includes a large stretch of cultivated fenland, is compared with that of the “natural” fen at Wicken and also with that of other districts.

2. The ecology of the various species is discussed and the conclusion is reached that the main factor determining why different species are found in different types of habitat is the time of year at which the female lays her eggs, and whether she lays them on damp ground or standing water.