Once they have emerged from the pupa case, our means of attacking mosquitoes are comparatively feeble, and for those that habitually pass most of their time in the open air practically _nil_.
In the case however of domestic species, which habitually shelter in houses, a good deal can be done in this matter; and, just as in the repression of other troublesome insects, such as fleas and bugs, scrupulous tidiness and cleanliness is by far the most important of all agencies. Useless, rarely dusted draperies and curtains, and untidy collections of clothing hung about on nails and pegs, instead of being kept in properly closed wardrobes, are the things that are mainly responsible for attracting and sheltering mosquitoes within houses, for they will not, if they can avoid it, remain in a well-lighted room, with freshly colour-washed bare walls.
In the tropics, the Italian villa with its frescoed walls and minimum of useless furniture, is the ideal that should be aimed at, and not the elaborate lumber warehouse of an English drawing-room; which, though comparatively harmless in our own climate, is about as well adapted for imitation in hot countries as the coat of the Polar bear in the Zoo is suited to our summer.
Perhaps our most effective agency in dealing with adult mosquitoes depends on the intense objection all species of these insects entertain to smoke.
That it is quite possible to effectually protect animals from mosquito bites by the agency of smoke alone, has recently been conclusively shown in the course of Mr. Power’s experiments on the prevention of horse sickness in South Africa; but, though most semi-civilised people seem to live comfortably enough in a smoky atmosphere, Europeans would find such a state of things intolerable; and the plan can only be utilised to drive mosquitoes out of houses, other methods being relied on to prevent their re-entering. Smoke from almost any source will put mosquitoes to flight, and if sufficiently intense will stupefy them; but certain special materials must be burnt if it is desired to kill them outright, and our _modus operandi_ must be varied according to the means at our disposal, for if we can only expect to annoy the insects sufficiently to drive them out of doors, the latter must be left open during the fumigation; whereas, if it is proposed to kill them, all openings must be closed as completely as possible, so that the fumes may reach the insects in as concentrated a form as possible.