climate. In humid regions, of course, it will rust more quickly than it
will where the climate is dry. The same may be said of galvanized steel
insect screen cloth.

Insect screen cloth made with 16 meshes to the inch is recommended, for
16-mesh screen cloth will keep out flies and most mosquitoes[9] and
other small insects which at times are found almost everywhere.

[Footnote 9: Where the yellow fever or dengue fever mosquito occurs,
18-mesh screen cloth (or 16-mesh screen cloth made from extra heavy
wire) should be used.]


FLY PAPERS AND POISONS.

[Illustration: FIG. 8.--Conical hoop flytrap side view. _A_, Hoops
forming frame at bottom. _B_, Hoops forming frame at top. _C_, Top of
trap made of barrel head. _D_, Strips around door. _E_, Door frame. _F_,
Screen on door. _G_, Buttons holding door. _H_, Screen on outside of
trap. _I_, Strips on side of trap between hoops. _J_, Tips of these
strips projecting to form legs. _K_, Cone. _L_, United edges of screen
forming cone. _M_, Aperture at apex of cone. (Bishopp.)]

The use of sticky fly papers to destroy flies that have gained access to
houses is well known. Fly-poison preparations also are common. Many of
the commercial fly poisons contain arsenic, and their use in the
household is attended with considerable danger, especially to children.
This danger is less with the use of a weak solution of formalin. A very
effective fly poison is made by adding 3 teaspoonfuls of the commercial
formalin to a pint of milk or water sweetened with a little brown sugar.