149 
etc. — are unharmed by such insecticides because they take their food 
from the interior of the plant, and so a contact insecticide must be 
used. 
The classification in the following synoptical list of insecticides 
is based on their most obvious distinctions, and the subsequent treat- 
ment corresponds to the order of the list. 
Dust or Liquid Sprays. p 
Stomach poisons for biting insects. 
Paris green, dry, with or without an adulterant 149 
Paris green, liquid spray 150 
Arsenate of lead 1 50 
Resin-lime mixture, with a poison 150 
Bordeaux mixture, with a poison 151 
Contact insecticides — for sucking insects. 
Kerosene emulsion 153 
Whale-oil soap solution 153 
Carbolic acid emulsion 153 
Hellebore decoction 154 
Insect powder (pyrethum or buhach) 154 
Tobacco decoction and nicotine preparations 154 
Lye-sulphur wash »i55 
Poisoned Baits — for biting insects. 
Poisoned bran mash 155 
Poisoned lettuce or clover leaves 155 
Repellents — for any insects. 
Carbolic acid and lime 155 
Tobacco dust 155 
Lime, dry 156 
Bordeaux mixture 152 
Ftuuigants — for any insects. 
Hydrocyanic acid gas 156 
Carbon bisulfid 158 
Sulphur 159 
Tobacco stems 159 
Nicotine preparations 159 
Paris Green — Dry 
Unmixed Paris green may be sprinkled upon plants, but the dan- 
ger of burning the leaves is lessened by adulterating it with flour. 
