568 MAN CONTROLS HIS ENVIRONMENT FOR WEALTH 



of their natural enemies, plant or animal; the improvement of 

 the honeybee ; and the introduction of new species of insects to 

 pollinate flowers not native to this country, are some of the prob- 

 lems to which these men have devoted their time. 



All the states and territories have, since 1888, established state 

 experiment stations, which work in cooperation with the govern- 

 ment in the war upon injurious insects. These stations are often 

 connected with colleges, so that young men who are interested 

 in this science may have opportunity to learn and to help. 



Bulletins on insects and their control are published by the 

 various state stations and by the Department of Agriculture. 

 Probably the most useful of these are the Farmers' Bulletins, 

 issued by the Department of Agriculture. 



The outline has been made up largely from these sources. 



ECONOMIC IMPORTANCE OF INSECTS 



Beneficial Insects 



Silk moth. — Larva spins a cocoon from which silk is made. 



Honeybee. — Adult produces honey and pollinates flowers. 



Bumblebee. ■ — Adult pollinates red clover and fruit trees. 



Ichneumon fly. — Female lays eggs in the bodies of harmful larvae (as the grape- 

 vine caterpillar and the tree borers) . The developing parasites feed on the hosts 

 and kill them. 



Dragon fly. ■ — Adult feeds on mosquitoes. 



Ladybird beetle. — Adult feeds on scale insects and aphids. 



Gall insect. — The developing larvae cause galls from which ink is made. 



Household Pests 



House fly. — Adult carries typhoid, tuberculosis, summer complaint, and other 



intestinal diseases. To exterminate, it is necessary to prevent breeding and kill 



overwintering flies. 

 Mosquito. — Adult carries malaria and yellow fever. May be exterminated by 



destroying the breeding places. 

 Body louse. — Adult carries typhus. Insects may be killed by sterilizing infected 



clothing and by bathing patients in an antiseptic solution. 

 Flea on rats. — Adult carries bubonic plague. Kill the rats. 

 Clothes moth. — Larvae eat clothing : wool, fur, etc. They may be controlled by 



snaking or brushing the clothing, and exposing it to the sun. The use of 



camphor or naphthaline on clothing which is packed away deters the moth 



from laying its eggs there. 

 Buffalo carpet-beetle. — Larva eats carpets. Spray benzine in the cracks in the floor 



and on the carpet. 

 Cockroach. — Adults are scavengers and are numerous around sinks and where food 



is kept. They may be exterminated with poison bait. Cleanliness is necessary. 



Garden and Fruit Tree Pests 



Potato beetle. — Larva eats leaves of the potato plant. Spray injected plants with 

 arsenate of lead or Paris green. 



