Some Special Injurious Insects 



171 



frequently of immense numbers. They feed upon the 



leaves, buds, tender stems, and even the roots in some 



sorts of plants. They 



do much damage by 



sucking the plant juices. 



Some species secrete a 



substance known as 



"honey dew," which is 



sought after by ants. 



The Ants care for the 



aphis and protect them 



from the depredations 



of predaceous insects. 



The scale insects are 



classed with the plant- 

 Fig. 110. The spring-grain aphis, a, wing- 

 less female; 6, larva; c, pupa; d, winged 

 migrant. After Webster, United States 

 Department of Agriculture. 



239a. Colonies of plant-lice may be found frequently on road- 

 side weeds, sometimes under the folded edges of leaves tended by 

 ants. Such a colony should be closely observed. Small tubes may 

 be seen on the abdomen of the lice covered with drops of honey 

 dew. The ants have a way of stroking the lice to make them give 

 up the honey dew. This action is often fancifully called "ants 

 milking their cows." 



240. Insects Injurious to Stored Grain. The insects 

 that damage stored grain are the larvse of moths and 

 beetles, and several species of weevils closely akin to 

 the plum-gouger and cotton boll-weevil. Corn, wheat, 

 peas, and many other seeds are often damaged by these 

 insects while stored. Some species are very destructive. 

 The "rice-weevil" is the most destructive, particularly 

 to corn, peas, barley, kafir corn, etc. The two most 

 common species of weevil are shown in Fig. 111. The 



lice. The San Jose scale 

 is the most serious re- 

 presentative. 



