No abstract

A list is given of all the species of mosquitos so far recorded from the Seychelles, with their distribution in so far as this is known. A number of new records are included based on collections made recently by one of us (E.S.B.).One species and one subspecies new to science are here described for the first time. The first full descriptions of the male terminalia and pupae of certain other species are included.Some notes are given regarding the taxonomy, bionomics and local distribution of the species concerned and the zoogeography of the groups to which they belong.Appendices are devoted to corrections to the second edition of “The Mosquitoes of the Ethiopian Eegion”, Vol. I by G. H. E. Hopkins, and to the mosquitos of other islands in the western Indian Ocean.

The studies described below were carried out between 7th June 1945 and 13th June 1946 at a field station near the village of Itowolo on the left bank of the Ogun river about three miles up-stream from the point at which it flows into Lagos Lagoon (Southern Nigeria) ( fig. 1). The vegetation in this area consists of moderately dense swamp forest with an average canopy height of between 50 and 60 feet, the latter figure appearing to be rarely exceeded except by occasional large cotton trees {Ceiba pentandra). The ground is intersected by numerous small creeks and the field st tion itself stood on a small island. At certain times of the year the creeks become choked with water lettuce (Pistia) and at such times they form an ideal breeding place for Taeniorhynchus africanus, Thco., Anopheles hargreavesi, fho»i, and other species of mosquitos. Lagos Lagoon is fringed with mangrove. The site was chosen in the belief that it would yield a large and varied mosquito population and in the event this proved to be the case. Over 30,000 mosquitos were taken in 23 catches and the population comprised more than 50 species. The principal object of the work was the accumulation of detailed information regarding the seasonal occurrence, biting cycle and vertical distribution of these mosquitos and for this purpose a continuous 24-hour catching technique was employed similar to that used by Bates (1944), andHaddow & others (1947). Details of Technique.Catching was carried out by adult Africans working in pairs on platforms at ground level, 22 feet, 40 feet and 52 feet. All the platforms were situated in a single tree (Cynometra sp.) and were numbered in the above order I, II, III and IV, respectively. The Africans worked stripped to the waist and with their legs bare and were changed from one platform to another every two hours. The first catch was largely of an experimental nature and was used to obtain a rough estimate of the relative attractiveness to mosquitos of individual Africans. The pairs were then arranged so that each should as far as possible be equally attractive and they were subsequently maintained unchanged except where illness or other causes necessitated a substitution. During the first 16 catches the allocation of the various pairs to platforms was made at random but after this it was planned so that no boy should have been on any particular platform during any particular hour an undue number of times. In view of the large possibilities of error due to the human factor in a technique of this kind it was thought better to use the boys in a random manner than to run the risk of imposing an artificial periodicity on the figures by alternating them regularly. The mosquitos were caught by the boys on themselves and their partners in small test tubes which were plugged with cotton wool and placed in linen bags each capable of holding a hundred. The bags were collected once an hour and each was provided with a label showing the time at which it was collected and

No abstract

SUB-GENUS STEGOMYIA (DIPTERA CULICIDAE) IN THE ETHIOPIAN REGION. II. DISTRIBUTION OF SPECIES CONFINED TO THE EAST AND SOUTH AFRICAN SUB-REGION By P. F. MATTINGLY CONTENTS information concerning the species treated in the first paper and with the rainfall of the Bor-Pibor-Torit area. The distribution of certain Palearctic Stegomyia is discussed in relation to the problem of the origins of the Ethiopian fauna and an account is given of a specimen of Aedes cretinus.