The eggs of the three species of bot-flies discussed in this paper are distinguished by the fact of that of G. haemorrhoidalis being the only one stalked. It is also longer than those of the other two species, which are of about equal length. Further, it is brownish black in colour, that of G. intestinalis being whitish yellow and G. nasalis yellow. The egg of G. intestinalis adheres to the hair by clasping flanges, which run only two-thirds of its length, whilst the flanges of the G. nasalis egg run almost the entire length.

The egg of G. haemorrhoidalis is not inserted nor screwed into the skin of the host. The eggs of G. intestinalis are laid indiscriminately on the body of the host, but preferably on the long hairs investing the inside of the foreleg. G. nasalis lays its eggs on the hairs of the intermaxillary space, and G. haemorrhoidalis on the hairs of the lips, preferably the lower.

Although a large variety of plant-galls are known in South Africa, only four have so far been determined to be caused by Coccids. These are of particular interest because no two of them are similar, and more remarkable still is the fact that no two of the insects belong to the same genus, nor apparently to the same sub-family. Under these circumstances it has been thought advisable to group them together without reference to their systematic position in this paper. The characters of the galls and insects may be seen from Plates iii and iv.

1. There appears to be a general similarity in the tastes of the different species with regard to various chemicals and foods; the tastes of Musca domestica and Phormia azurea, in many cases, being found to approximate most nearly. It will be interesting to discover whether there is a closer correspondence between the sense-organs of these flies than between these of other species.

2. These experiments emphasise the extreme curiosity of house-flies, and again show the catholicity of their tastes and the difficulty of finding any substances which will either attract or repel all those that come near it. The mineral and tar oils seem to be amongst the most repellent substances. With regard to poisons, good results were obtained with sodium iodate, large numbers being killed when very small amounts were used, although it did not always attract many flies. Sodium iodate has the disadvantage of being very expensive. But further experiments require to be made before any definite conclusions can be arrived at as to the importance of the iodates of sodium and other metals as poisons for general use.

3. House-flies were not found to show any colour-preference.

4. For house-flies the optimum temperature was found to be between 36°–44° C., the maximum and minimum between 55°–58° C. and 10°–13° C., respectively.

5. It appears that curiosity plays an important part in causing house-flies to come to baits and to investigate traps, etc., although the senses of smell and to a less extent that of sight are also concerned; the former, however, to a much less extent than it is with blow-flies, and it appears to be most used when the flies are close to the baits.

In the course of the operations for controlling mosquitos on the Macedonian front some time, necessarily limited, was devoted to collecting parasitic or noxious arthropods, and a list is here given, more particularly of those affecting man. One or two other noteworthy species are also recorded.

The material for this paper was forwarded to the author by Dr. Guy Marshall, of the Imperial Bureau of Entomology, and was collected by Mr. C. B. Williams.

The insects were said by him to be parasitic on a Cercopid of the genus Clastoptera, which was found attacking cacao trees. This highly unusual habit gives much interest to the species. Unfortunately the number of individuals sent was quite inadequate to enable one to deal satisfactorily with such small and obscure insects, especially as shrivelling takes place to a different extent in various individuals, which renders the provision of a reasonably large number more necessary than in more normal forms of fly. The individuals sent included three pinned ones of a species from Trinidad (West Indies), and one pinned one of a species from Panama, together with the fragments of two others of the latter species in spirit. In spite of the paucity of material, it was felt to be desirable to put on record as fair a description as could be made under the circumstances. Two of the individuals of the Trinidad species were of one sex, and the third was apparently the other sex of the same species. The two former had all the appearance of representing the male, having brighter eyes, darkened wings, and the general facies of that sex. The genitalia were small and hidden in a terminal hood, such as is found in Drosophila melanogaster and Leucophenga maculata, but it was smaller than in either of these, even than in the latter, in which the hood is only moderately open at the tip, while widely so in the former.

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.