At the time of my visit (1916) the froghopper could not be considered as a very serious pest of sugar-cane. It was in some spots extremely abundant in the fields, but by far the larger number were feeding on the grass. Even at its worst the numbers nowhere approached those found in Trinidad during an attack, and the canes suffered very little visible damage. It would, however, be very difficult to distinguish the present conditions in British Guiana from those that must have prevailed in Trinidad before the insect became a regular pest. In view of this, the froghopper should always be regarded as a possible great danger in Demerara, and any reasonable precautions and preventive measures should be taken.

Lycidocoris, Reut. & Popp., Trans. Ent. Soc. Lond., 1911, p. 409; Popp., Acta Soc. Scient. Fenn., xli, p. 182 (1912).

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.

When studying the injurious insects of a plant it is, as a rule, easy when several insects occur together to isolate them and breed them separately in order to ascertain their parasites. In some instances, however, this method is unworkable, and this applies particularly to the often very complicated fauna of the cones of the coniferous trees.

Three species of Braconidae have now been bred in Demerara from the larva of the cane-boring moth, Diatraea saccharalis: Ipobracon grenadensis, Ashm., which I have previously mentioned (Ann. Mag. N.H. (8) xx, 1917, p. 244), and Ipobracon saccharalis, sp. n., both of which belong to the subfamily Braconinae; and Microdus diatraeae, sp. n., which belongs to the subfamily Agathinae.

In the course of an investigation into the froghoppers (Cercopidae) of the genus Tomaspis found on sugar-cane in Trinidad and the neighbouring countries, made on behalf of the Government of Trinidad, I visited Grenada in December 1916 and spent a few days investigating a small but severe outbreak of froghoppers in that Island. The following notes seem of sufficient interest to be published without further delay.