SCREENING OF HOUSES 359 
been of a standard character, and the operations at these points will be more 
fully mentioned in subsequent paragraphs. 
In other parts of the world many striking examples of value of anti-mosquito 
work have been shown comparatively recently, and several of these will be de- 
tailed later. 
In the pages that follow the aim has been to give a full consideration to the 
subject of remedies and preventives, discussing not only those which have been 
found to be of the greatest value, but also others of lesser or even no value, since 
an expression of opinion concerning all may well be considered desirable. A 
large part of the following information has been published by the senior author 
under the title “ Preventive and Remedial Work Against Mosquitoes ” as Bull. 
88, U. S. Dept. Agr., Bur. Ent., 1910. For a condensed summary of the best 
remedies the reader is referred to Farmers’ Bulletin 444 of the U. S. Depart- 
ment of Agriculture, which may be had for the asking. 
PROTECTION FROM BITES. 
SCREENS AND CANOPIES. 
Such obvious measures as the screening of houses, the use of netting for beds 
and the wearing of veils and gloves after nightfall in badly infested regions, 
need no consideration in detail. But even in such an apparently simple matter 
as house screening certain points must be taken into consideration. It may 
be incidentally stated that with proper treatment of breeding-places screening 
is unnecessary. The expense to which the people of the United States go for 
screens against mosquitoes and flies is enormous, and has been estimated at 
$10,000,000 annually. 
In screening a house, as Doctor John B. Smith has pointed out in his Bulletin 
No. 216 of the New Jersey Agricultural Experiment Station, the attempts fre- 
quently fall far short of protection: 
“ Adjustable, folding, or sliding screens are never tight, and when the insects 
teally want to get indoors they work their way patiently between the two parts 
of the screen or between its frames and the window. But even a well-fitted 
screen either sets tightly into the frame or, running like a sash, may offer leaks 
when a window is only partly opened. . . . There is abundant opportunity for 
the insect to get in between the net and lower cross bar; in fact, there is no real 
protection at all. Where the netting is fixed to the outside of its frame, so that 
there is no space between it and the lower part of the sash, the insects neverthe- 
less find their way in between the window sashes. . . . It has been already said 
that the mosquitoes will, in certain seasons, attempt to make their way through 
the screens, and they have less trouble with wire netting than with any other 
because the meshes are even in size and the strands smooth. Some of the fabrics 
used for nettings, especially of the cheaper grades, have the threads so fuzzy that 
it is simply impossible for the mosquitoes to make their way through, and they 
rarely even try it except where there is a tear, or where the threads have been 
spread apart leaving an unusually large opening. Where an onslaught is made 
on wire netting it can be checked by painting lightly with kerosene or oil of 
citronella. I have tried both and found them successful.” 
In addition to these mechanical difficulties it often happens that the cellar 
and attic windows of houses are not screened. This is a great mistake, since 
