Some additional fruit-flies of the genus Dacus (s.l.) from the Ethiopian Region have been recently submitted to me for study by the Imperial Bureau of Entomology, through the kindness of Dr. G. A. K. Marshall, the Director.

The oyster-shell or mussel scale (Lepidosaphes ulmi, L.) (fig. 1) is too well known to need any particular introduction ; suffice it to say that this insect has followed its principal food-plant, the apple tree, over the world. Though usually considered a serious pest in places in which it has been long established, such as England and

Canada, it is not increasing. There must then be agencies at work destroying annually about 98 per cent. of the progeny of each pair of scales. In different countries these agencies may differ greatly. It is the purpose of the present paper to give a general outline of the principal factors operating in the control of this scale in Canada, and more especially in Eastern Canada. The study, which has been carried on under the direction of the Dominion Entomologist, Dr. C. Gordon Hewitt, is based on the literature of the subject and on the examination of about eighteen thousand egg-masses of scales collected, between September 1916 and April 1917, from representative places throughout Canada. Most of this material was gathered by the officers and friends of the Entomological Branch and mailed to the Dominion Entomological Laboratory at Fredericton, N.B., for examination. The names of these gentlemen appear in the analysis table (on page 191) opposite their respective collections and it is a pleasure to acknowledge their kindly assistance. Each 100 of these egg-masses was, so far as practicable, an average 100 selected from several twigs of one tree or bush. So far as possible, collections were made from five trees or bushes at each observation point.

Like Aspidiotus, except that the adult ♀ remains enclosed in the skin of the 2nd stage, with the exception of the pygidium, which extends through the hind part of the enclosing skin, beyond the posterior margin of the 2nd stage female (fig. 114).

Very little is known about the Dipterous Family Lonchaeidae in the Ethiopian Region, notwithstanding the small extension of the group (almost limited to the two main genera Lonchaea, Fallén, and Palloptera, Fallén), and in spite of its economic importance. Some tropical or sub-tropical species of Lonchaea pass their larval stage in fruits, in which they sometimes occur in company with Trypaneids, and are often mistaken for them, being thus comprised under the same name of “ fruit-flies.”

The larva figured in the accompanying illustration was obtained from the urinary tract of a native of Mongalla Province, Anglo-Egyptian Sudan. A careful search through the literature at our disposal has failed to reveal any reference to a similar case of parasitism of a Coleopterous larva in the urinary tract.

In considering the methods of coping with any group of injurious insects, the study of natural enemies must occupy an important place in any laboratory or field investigations that are carried out in connection with such pests.

On arriving at Nsazi Island on Victoria Nyanza in July 1918 to carry out some experiments with Glossina palpalis and rinderpest, I was at once struck by a marked diminution in the numbers of the fly on this and the neighbouring islands. Since the days of the first Commission of the Royal Society, the small island of Kimmi, about three-quarters of a mile N.E. of Nsazi, has been noted for the numbers of its tsetse. I had with me some of the original Mpumu fly boys and others who had worked on these islands with Fiske and Carpenter from 1911 to 1916. Their evidence on such matters is reliable, as they receive a bonus for their catches. They were all unanimous that the fly on Kimmi, Nsazi, and Tavu Islands had decreased very markedly in numbers. My own observations confirmed this in each case.