150 



materially from that employed by the author in 1920, and the views 

 of the first-named seem to have influenced the names adopted by 

 Wesenberg-Lund [ix, 82] and Lang [viii, 139]. In the author's 

 opinion the nomenclature of the writers named cannot be accepted 

 in many particulars, even from the standpoint of the rules governing 

 nomenclature. He therefore examines the most important publica- 

 tions up to and including those of Meigen, and discusses the synonymy 

 of the various species as differentiated by modern technique, 



SchDffner (W.) & Hylkema (B.). Malaria in Belawan during the 

 Construction of the Ocean-Harbour. — Meded. Burg. Geneesk. 

 Dienst Ned.- Indie, Batavia, English edn., 1922, no. 1, pp. 47-79, 

 18 figs., 1 map, 3 charts, 6 tables. 



Belawan is an alluvial island in the delta of the Deli and Belawan 

 rivers, Sumatra, where the construction of a sea-harbour was begun in 

 1917, The authors' investigations there extended from 1918 to 1920. 

 Like the entire littoral zone, the island is densely overgrown with 

 mangrove forests. Only a small portion was used for the harbour 

 works, near which the village was situated. The remaining area, 

 intersected by creeks, was regularly flooded by the tide until dykes 

 forming part of the new works effected a gradual change, resulting in 

 the formation of new breeding-places and consequent increase of 

 Anopheles ludlowi. Virgin mangrove forests are almost free from 

 malaria, and it is almost certain that Belawan first became malarious 

 owing to the construction of the railway and port in 1885-88. 



In their modification of the official sanitation plan the authors 

 urged that a cleared isolation zone of 550 yards was useless in view of 

 the innocuousness of the mangrove forest and the radius of flight of 

 A. ludlowi, that any clearing needed for enlarging the settlement 

 should be immediately followed by reclamation work on the cleared 

 area, and that no subsequent felling or digging should be allowed 

 in the mangrove forests within a radius of two miles from the settlement. 

 In 1919 about 300 Chinese labourers came to carry on the actual 

 harbour work, and by 6th June many cases of malaria occurred, two- 

 thirds being mahgnant tertian. By September this focus of infection 

 was no longer present, and in the subsequent months a complete 

 change in the Anopheline fauna occurred. A . ludlowi decreased, and 

 the few other species that occurred soon disappeared, so that by 

 December the island was almost free ffom Anophelines. This state 

 of things obtained in 1920 also. 



The larvae found at Belawan were A. umhrosus, in small numbers 

 in the forest in muddy, shaded pools and holes not regularly flooded 

 by the tide ; A. hyrcanus {sinensis) in small numbers, chiefly in salt 

 water ; and A. ludlowi, the most common species, only on the cleared 

 areas. In Juty 1918 A. ludlowi left the small pools among grass, 

 where it had been observed since the early part of the year, and bred 

 in large, fishpond-like pools which had become suitable in the inter- 

 vening six months. Swellengrebel has pointed out a similar change 

 of habitat [R.A.E., B, vii, 53], which may nullify the effect of measures 

 against specific breeding-places. Newly-formed pools, due to excava- 

 tions or reclamation work, require from one to six months or more to 

 become suitable for the mosquitos, the time being longer the easier the 

 communication with the open sea, as the growth of vegetation adapted 

 to the hatching of the eggs of A . ludlowi is thereby delayed. Brackish 

 water favours A. ludlowi, the development of which continued in water 



