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danger attending such attacks could be minimised, if not prevented ; 

 but there is no chance of such a service being available before the 

 troops return from abroad. Cases of malaria in persons who have 

 never been out of the country have already been reported. The 

 Local Government Board is therefore turning to the last line of defence, 

 namely, the control of Anophelines. 



Three species of Anophelines occur in England ; Anopheles maculi- 

 •pennis, the commonest malaria carrier in Europe, A bifurcalus, 

 and A. plnmheus (nigripes). The last-named is rare and of rather 

 unusual habitat. It occurs in Epping Forest, where the larvae have 

 been taken from holes in beech trees, but there is no evidence that 

 this species is able to convey malaria. A, bifurcalus is a malaria 

 carrier, but is much less common than A. macnlipennis. 



There is considerable difference between the breeding-places of 

 Anophelines and those of other groups of mosquitos. The former, as 

 typified by A. inaculipennis, frequent open sunlit water. Small, 

 impermanent and very shallow collections of water such as appear 

 in the holes made by horses' hoofs, or waters that are much obstructed 

 and clogged with weeds, require much more careful attention as 

 breeding-places than the more permanent pools and streams, the latter 

 being generally tenanted by enemies of mosquito larvae while the 

 former are not. 



The inventions of man for combating mosquitos are summarised 

 as follows : — The use of mosquito curtains, screening of dwellings, 

 the application of repellents, the destruction of adults by traps, 

 fumigation or spraying, the removal of cover near houses and the cutting 

 of trees, bushes and grass. Control of the larval and pupal stages is 

 effected by drainage of surface-water and swamps, the filling of pools 

 and water-holes, the removal of weeds in streams and ponds, deepening 

 the margins of ponds, filling in of hoof-holes, oiling of water-surfaces 

 and the penalising of persons who allow mosquitos to breed in lily- 

 ponds, rock-gardens, sw^amps, water-tanks, and other domestic supplies 

 of water, and those who leave about discarded tins and empty bottles. 

 The methods of control must be chosen to suit the conditions of a 

 particular district ; it must be considered whether the filling in or 

 oiling of a pool will destroy natural enemies of the mosquito ; the time 

 of undertaking the control measures must be duly considered in regard 

 to the time of breeding of the mosquitos. The first steps should be 

 the drainage of swamps (not bogs) and the clearing of ditches to secure 

 a better level and quicker flow. All small temporary collections 

 of water should be filled up or regularly oiled as long as they contain 

 water. Water-tanks and butts should be kept stocked with a few 

 small fish or carefully screened with wire netting. Certain kinds of 

 trapped surface-water drains that afford breeding-places for Culicines 

 should be treated during dry weather with crude naphthaline or 

 disinfectants. The water-holes often found about the roots of old 

 beech trees should be filled in with sand or leaf mould. Larvicides 

 should be carefully chosen. Heavy oils are best in hot climates as 

 they do not evaporate too rapidly ; in cool climates light oils can be 

 used and the oil can be emulsified with a soap solution with equally 

 good results ; such an emulsion will kill at a dilution of 1 in 20,000. 

 For Anophelines in running water and for any species in salt water, 

 the Panama larvicide, made of crude carbolic acid and resin soap, 



