2 
PROCEEDINGS OF THE ROYAL SOCIETY OF QUEENSLAND. 
problem. Anyone starting out to control all the mosquitoes in a large 
area is faced with an almost hopeless task requiring an expenditure of 
millions of pounds, an abundance of labour, and endless patience. The 
result is that such a campaign is rarely started, or soon discontinued. 
There are at least three distinct problems, each of w v hich is caused by a 
separate complex of species, each affecting the community in a different 
way, and each requiring specialised methods of control. These three 
problems can be described as follows, and will be considered in 
detail — 
(a) The Domestic Mosquito Problem; 
(b) The Freshwater Mosquito Problem; 
(c) The Saltwater Mosquito Problem. 
( a ) The Domestic Mosquito Problem. 
The complex of mosquitoes responsible for this problem comprises 
those breeding in city and suburban areas, in and adjacent to dwellings. 
From the point of view of the majority of the people of Queensland, 
this is the most important problem of the three. It is associated with 
the spread of human diseases, and also with the existence of a very 
definite nuisance. There are two important species of mosquito 
responsible for this problem, and it is desirable and convenient to treat 
them separately. 
Perhaps the more important of the two is the Dengue mosquito 
(Aedes aegypti). This cosmopolitan mosquito is well established 
throughout Queensland and is responsible for periodical epidemics of 
Dengue Fever. It is probably the most domesticated of all mosquitoes 
and appears to have a definite preference for human blood. As a rule 
it breeds only in vessels containing comparatively clean rain- or tap- 
water. Tanks, faulty guttering, old tins, vases, rubber tyres, &c., are 
the usual breeding places. Any artificial container capable of holding 
water for a week or more is likely to breed this mosquito. Although 
Aedes aegypti , which is essentially a day-biting mosquito, is a cause of 
real discomfort, it is considered first because it is the chief carrier of 
Dengue Fever, which has been all too common in Queensland during the 
last few years. Dengue Fever is not a fatal disease, except, perhaps, 
in the case of very young children, but it seriously affects the life and 
health of the community. During the last few years, probably aided by 
the war, it has been unusually prevalent; and unless a drastic change 
occurs in the attitude of the householder, it will continue to cause a 
great deal of loss of time and money. On the average a case of Dengue 
means two or three visits by a doctor, medicine, and usually about two 
weeks away from work. In one coastal town a firm engaged on war- 
work lost 27,000 man-days from Dengue alone at a time when both the 
firm and the country could ill afford the loss. 
Control of Aedes aegypti. 
The control of this mosquito is not difficult, and a determined 
effort by members of the community could obtain most satisfactory 
results in two to three years. As with all mosquito problems, under 
peace-time conditions Aedes aegypti can be controlled by the permanent 
elimination of all natural breeding-places. Perhaps the greatest single 
factor in the maintenance of this mosquito in our midst is the prevalence 
of large numbers of tanks not adequately protected from mosquitoes. 
During the war, when labour and materials are not available, there is 
some excuse for this state of affairs; but after the war, renovation of 
house-tanks should receive very early consideration. It is to be hoped 
