On 25th August 1914, the medical officer in charge of a rubber estate in Malaya wrote to the manager a report about a new method of polluting Anopheline breeding-places: “It will interest your Directors to learn that by oiling with the mixture in use on Sungei Way, one of the ravines in the West Divisions has been kept free from Anopheles for several months. Formerly they bred freely in it. I am encouraged to think that this is not merely due to the physical difficulty the larvae would have of getting air when oil is on the water, but that some change has actually taken place in the water as a consequence of the oil, and a change which would make it uncongenial to the stream-breeding mosquito. My reason for thinking this is that in the bottom of the ravine a green slime has developed, in the presence of which I have never found dangerous anophelines” (Watson, M. 1921). Before 1914 oil had been used on standing water, and poisons had been used in running water (Howard, Dyar & Knab, 1912) to reduce the breeding of mosquitoes. But this discovery, that it could be effectively and economically used even on fast-flowing streams to control Anopheles, made the use of oil par excellence the great standby in emergencies of malaria; while it may be the method of choice if control measures are only required for two or three months in each year.

The work which has resulted in the following paper has been carried out in the Department of Entomology of the British Museum (Natural History), at the request of Professor J. W. Munro and on behalf of the Pest Infestation Laboratory of the Department of Scientific and Industrial Research. The critical material used has been mainly that already available in the British Museum, but it has been partly supplemented from Professor Munro's resources.

1. Melittomma insulare is a serious pest of coconuts in parts of Seychelles and Madagascar.

2. In Seychelles the insect is only known from a few of the islands, its distributio being dependent on the original distribution of its primitive host-plants which are two species of endemic palms.

3. The eggs are laid under cover in batches and hatch in eleven days. The larvae feed in galleries in the base of the trunk for an indefinite period depending on the sappiness of the wood. Pupation takes place in the enlarged end of a boring. The adult is nocturnal and short-lived.

4. The damage caused depends on the age and situation of the tree which is attacked. Other things being equal trees growing on good soils are damaged least.

5. Several other species of insects are associated with Melittomma, but all are of minor importance.

♂♀. Derm black, with dense sandy grey scaling, the elytra with a small brown spot at the base of the suture and often some indefinite brownish markings elsewhere; underside grey.

1. G. pallidipes almost invariably attacks man on the leg from the knee downwards.

2. G. brevipalpis may attack man anywhere and not infrequently on the head.

3. Both species fill themselves readily with human blood once an attack has been made.

4. Neither sex of either species attacks man unless very hungry, as indicated by the very low mean fat content in the captures.

5. G. brevipalpis is apparently more reluctant even than pallidipes to attack man, and the fat contents in flies caught on man are proportionally lower than in the case of pallidipes.

The relative size of the compound eye constitutes a good phase character in Locusta migratoria migratorioides, the ratio E/D (length of elytra to the maximum vertical diameter of eye) being over 15 in the males and about 16 in females of the gregarious phase, as against about 13 in the males and about 14·5 in the females of the solitary phase.