360 MOSQUITOES OF NORTH AMERICA 
mosquitoes will enter these windows and pass the winter in both cellars and 
attics. They also descend unused chimneys, so that fire-places require screening. 
With regard to bed canopies there is reason for the greatest care. There 
should be ample material to admit of a perfect folding of the canopy under the 
mattress, and the greatest care should be taken to keep the fabric well mended. 
It often happens in mosquito regions that little care is taken of the bed nettings 
in the poorer hotels, and it is necessary for perfect protection that a traveler in 
the Southern States should carry with him a pocket housewife and should care- 
fully examine his bed netting every night, prepared to mend all tears and 
expanded meshes. 
Veils and nettings for camping in the tropics are absolute necessaries. Light 
frames are made to fit helmet-like over the head and are covered with mosquito 
netting. Similar frames readily folded into a compact form are made to form 
a bed covering at night, and every camping outfit for work in tropical or 
malarial regions should possess such framework and plenty of mosquito netting 
as an essential part of the outfit. 
An illustrated advertisement in Ross’s “ Mosquito Brigades ” shows a folding 
hood mosquito net especially for the use of travelers when taking rest. This is 
64 feet long, 4 feet wide, and 2 feet high. It is a frame arrangement which can 
be opened by the traveler so as to envelop himself when he is lying down. The 
frame is easily carried in the hand, being only 40 inches long by 4 inches in diam- 
eter when folded. There is also given an illustration of a small, compact mos- 
quito house for use by travelers while writing, reading, or taking their meals. It 
is large enough to contain two persons seated, and is constructed with a frame 
which is earily portable. The frames are manufactured by White & Wright, 
surgical instrument makers, 93 Renshaw Street, Liverpool. No doubt other 
apparatus of the same kind is manufactured and to be purchased at large out- 
fitting establishments, such as the Army and Navy Stores in London. 
Some attention has been paid to the subject of the size of the mesh of screens 
with especial reference to the yellow-fever mosquito. Working Party No. 2 of 
the Public Health and Marine-Hospital Service, at Vera Cruz, conducted a few 
experiments to determine the question of the size of the mesh. Their experi- 
ments were conducted by placing screens with a varying number of meshes to 
the inch over breeding-jars and putting bananas, syrup and other food on the 
other side so as to tempt the hungry mosquitoes to pass through. The fruit 
and other food was placed in a jar which was inverted over the mosquito breed- 
ing-jar, and a piece of gauze or netting was inserted between the two jars so 
that the mosquitoes would have to pass through the meshes in order to appear 
in the upper jar. As a result it was found that both males and females passed 
through a netting containing sixteen strands or fifteen meshes to the inch, but 
could not pass twenty strands or nineteen meshes to the inch. It therefore be- 
came evident to these observers that the large-meshed mosquito bars ordinarily 
used in Vera Cruz would not offer proper protection and that window screening 
must also be of a finer mesh than is sometimes employed. 
