The Oyani Valley is in the South Kavirondo native reserve of Kenya Colony. The river from which the valley takes its name rises in the Kilgorris groups of hills in and near the south-west corner of the Masai Reserve. The Oyani enters South Kavirondo at a point about 1°0' South by 30°35' East; it flows in a general north-westerly direction through the Kanyamkago location and joins the Kuja River about eighteen miles above the junction of the Kuja and the Gori Rivers.

♂♀. Derm piceous, with very variable grey and brown scales, not forming any definite pattern, usually the brown scales predominating, but sometimes the grey; the scales on the elytra broader and longer than usual, fairly dense but not entirely concealing the derm.

The increase of air transport and the potential dangers therefrom, together with the related problems are investigated.

The introduction of a malarial vector from one faunal region to another, and the effects thereof are discussed.

The literature of the epidemiology of yellow fever, particularly the work done on the insect vectors and the susceptible animals is reviewed, and the implications thereof in connexion with air transport are considered.

The air communications of the world are shown as a map; maps of Africa and South America showing the air routes and yellow fever areas are presented.

The control of air ports and aerodromes is discussed, in connexion with which the literature on the flight-range of insects, the dissemination of insects by wind, and insects and the upper air is reviewed.

A comparison is made between the insects collected from the terrestrial zone of the atmosphere and those from the upper air.

The work done upon insects found in aircraft is reviewed, and the results incorporated together with those from Khartoum in a “World List” table. The work done in Khartoum is described, and this, together with other workers' results, is analysed.

A comparison is made between insects found in the terrestrial zone, the upper air or “Plankton zone” and those found in aircraft.

The medical, veterinary and agricultural aspect of insects found in aircraft is discussed.

The control of insects in aircraft is considered and suggestions made for future research.