22 INSECTS AFFECTING VEGETATION 



Insects with a sucking mouth : 



All wings scaly: Lepidoptera. 



Only two wings: Diptera. 



Upper wings half leathery and half membranous : Hemiptera. 



II. 



1. With two wings: Diptera. 



2. With four wings : 



A. Upper and lower similar: 



a. All wings scaly : Lepidoptera. 



b. All wings naked or a little hairy : 



1. Wings with numerous veins : Neuroptera. 



2. Wings with few veins : Hymenoptera. 



B. Upper and lower wings dissimilar: 



a. Mouth-parts forming a sucking tube: Hemiptera. 



b. Mouth-parts not forming a sucking tube: 



1. Upper wings horny: Coleoptera. 



2. Upper wings like pergament: Orthoptera. 



(Bui. 28 Minn. Agr. Exp. Sta.) 



METHOD OF USING THIS VOLUME. 



To determine what insect or disease is injuring your crops and 

 the methods of prevention or cure, first carefully note the nature of 

 injury to the particular crop. Then secure specimens of the injured 

 plants and look for the pest. When you find the insect, if such be 

 the pest or the diseased portion, if no insect is discovered, go to your 

 library, get down this volume and look in the index for the name of 

 the plant affected. Turn to the page indicated and read carefully 

 through that portion until you come to the description of an injury 

 which appears to be identical to that you have in hand. Read this 

 over carefully and apply the remedy given. Be sure to note whether 

 any cultural directions are given, regarding the future treatment of 

 this specific crop, that will help to insure the freedom of the plant 

 from this kind of an attack another year. 



Example. Your whoa, appears yellow and is falling down 

 badly. Examine the fallen stalks carefully. You find that < 3 

 base are several constrictions and in the sheaths are small brown 

 bodies, like flax-seed. Going to your library you turn to wheat in- 

 sects and find that the description of the injury by the Hessian fly 

 corresponds to the injury in your grain. The remedy given is to 

 burn the stubble after harvesting to kill many of the second brood; 

 in addition, the volume tells you to plant your wheat that fall as late 

 as possible, without endangering your gram by winter killing. This 

 late planting prevents the second brood from depositing eggs which 

 will hatch the following spring and injure the grain another year. 



In any case the remedy will be given following each insect but 

 for a complete discussion of the formulas and methods of making 

 and using the various insecticides, consult the sections on the prepara- 

 tion and uses of insecticides, pages 362-399 and 656-666. 



