of cells beneath the ones already built. They 
attach each new comb with a sturdy paper stem. 
Polistes also enlarge their nests. But instead 
of building new layers, they add cells to the 
original comb. 
Among mud daubers, nest building is com- 
pleted when the female has constructed a group 
of cells, provisioned them with spiders, and de- 
posited eggs. She may then construct a second 
group of cells in another location. 
With the onset of cold weather, the paper nests 
of the hornets, yellow jackets, and Polistes are 
abandoned by the insects. The old nests are never 
again used. They usually disintegrate or are torn 
to pieces by birds or squirrels. The insects are 
perpetuated over the winter by the hibernating 
queens. 
The clay-cell nests of the mud daubers do not 
disintegrate. The insects overwinter in them in 
the pupal stage. 
HOW TO CONTROL WASPS 
Wasps can be controlled by applying an insecti- 
cidal spray or dust to their nests. Chlordane, 
dieldrin, and DDT are effective for this purpose. 
They are available from insecticide dealers as 
emulsifiable concentrates and wettable powders, 
from which sprays can be prepared, or as dusts and 
oil solutions ready for use. 
Use a household or garden-type applicator for 
spraying and a hand duster for dusting. 
Dusts are easy to apply to some hornets’ and 
yellow jackets’ nests, whether above or under the 
ground. The extension tube on a garden-type 
duster can be inserted into the nest opening. Two 
or three strong puffs of dust will filter through 
the nest, and will usually kill the colony within 24 
hours. A shovelful of moist earth thrown over 
the entrance of a colony in the ground after treat- 
ment will prevent the dying wasps from gaining 
the surface. You can also treat an underground 
nest by pouring several ounces of carbon tetra- 
chloride into the opening and then plugging it with 
absorbent cotton. 
Do your control work at night when the wasps 
are less active and most of them are in their nests. 
Apply insecticides to the nests, concentrating on 
the openings. Use (1) a 5- or 6-percent chlordane 
dust, a 5- or 10-percent DDT dust, or a 1-percent 
dieldrin dust, or (2) a 2-percent chlordane oil solu- 
tion, a 5-percent DDT oil solution, or a 0.5-percent 
dieldrin oil solution, or (8) an emulsion or suspen- 
sion spray. An emulsion spray can be prepared by 
mixing a chlordane, DDT, or dieldrin emulsifiable 
concentrate with water; a suspension spray, by 
mixing a DDT or a chlordane wettable powder with 
6 
water. You can prepare effective sprays for con- 
trolling wasps by using any one of the formula- 
tions given in the following table: 
Emulsifiable Tablespoonfuls to 
concentrates 1 quart of water 
25-percent, DDT.) ees 
50=percent DDT) = eee 
45-percent chlordane. . . .. . 4% 
15=percent dieldrin’... 39-4 ane 
Ounces to 1 quart 
Wettable powders of water 
25-percent DDTy |. =) > sean SaeenG 
50-percent DDT). => & ee ees 
40-percent chlordane) =). 4) eels 
It may be possible to dislodge hornets’ and yel- 
low jackets’ nests and dispose of them in a sack 
or other suitable container. Before dislodging 
a nest, plug the opening with absorbent cotton 
that has been soaked in carbon tetrachloride; the 
fumes will stun the wasps and you can then move 
the nest with less danger of being stung. Work 
quickly. After the nest is dislodged, burn or bury 
it, or put it into a can containing a few table- 
spoonfuls of carbon tetrachloride and seal the can 
tightly. 
A 5-percent DDT oil solution, a 2-percent chlor- 
dane oil solution, or a 0.5-percent dieldrin oil solu- 
tion can be used effectively to control wasps in the 
home. (Note.—Do not use dieldrin or chlordane 
for overall spraying of the interior of rooms.) 
Spray screens, window frames, and other places 
where wasps generally crawl. You can kill in- 
dividual wasps with a fly swatter or with a direct 
spray from an aerosol bomb or household sprayer. 
PRECAUTIONS 
Most insecticides are toxic. . . . Keep in- 
secticides where children and pets cannot reach 
them. . . . When applying them, do not contami- 
nate food, dishes, or kitchen utensils. . . . Do 
not store them with food. ... Do not breathe 
the spray mist or dust. If insecticide is 
spilled on the skin, wash it off promptly. ... 
Change your clothes if you spill insecticide on 
them. . . . When you have finished applying an 
insecticide, clean the sprayer or duster, and wash 
all exposed surfaces of the body with soap and 
water. . . . Use carbon tetrachloride outdoors; 
avoid inhaling its fumes. 
CICADA KILLERS 
Cicada killers are solitary, ground-nesting 
wasps that are common in many sections of the 
country. They are large (about 114 inches long) 
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