In this short report it is proposed to deal exclusively with the blood-sucking insects and other Arthropods which are, or may be, implicated in the transmission of disease in man and animals. In this connection, however, certain aspects, geographical and geological, are necessarily involved, but these will be introduced only when considered to be directly relevant to the main issue.

The writer's original intention in publishing this paper was to give a key for the identification of those African mosquitos which might be taken by the nonspecialist for species of Culex, without attempting to form any opinions as to the value or limits of allied genera. A study of the insects, however, led to the realisation that scale characters, in this group at least, are not of very great value for separating genera, and consequently the present paper gives the author's views of the classification of the Culex group, and is more complete than it might otherwise have been. Time has not yet been available to deal with those species which have flat scales on the top of the head or on the scutellum (Stegomyia group).

The Entomological Research Committee has received from Zomba four specimens of a new species of flea which is related to the genera Leptopsylla, Roths. (1911; type musculi, Dugès, 1832) and Palaeopsylla, Wagn. (1902; type minor, Dale, 1878 = gracilis, Tasch., 1880) but differs so much from the species belonging to these genera that it requires a separate genus. The species is especially remarkable for the development of its head and buccal organs (fig. 1). The mandibles as well as the labrum are very broad, particularly the former, and closely resemble those of Spilopsyllus cmiiculi, Dale (1878), and the Sarcopsyllidae. This peculiar parallelism also obtains in the labial palpi, which show a reduction similar to that which occurs in the fleas mentioned, being but feebly chitinized and consisting of only three distinct segments. The size of the labrum and mandibles suggests that the species fixes itself to the host by means of these organs in the same way as Spilopsyllus cunieuli, i.e., more permanently than do the majority of fleas. The structure of the head bears out this surmise inasmuch as the buccal slit extends far upwards, the frons being short, which allows the piercing organs to assume an almost horizontal position when being driven into the skin of the host.

The Oshogbo and Ilesha districts of Southern Nigeria are contiguous and are situated in the north-east corner of the Western Province. They are bounded on the north and east by Northern Nigeria, on the west by the Oyo district, and on the south by the Ibadan and Ondo districts of the Western Province, and by a small part of the Central Province.