INSECTS OF THE FIELD. 83 



BUGS All bugs are insects but all insects are not bugs. 

 When we speak of bugs we mean such insects as the many kinds 

 of plant lice. Aphis (plural, aphides) is another name for a 

 plant-louse. This order of insects is known as the half-winged 

 (hemiptera). Some have only two wings and some have four. 

 We find plant lice quite common on many house plants 

 and garden plants. Orchard trees, cabbages, hops and 

 many other plants are much infested by lice, some very small, 

 some large enough to be easily studied. There are some also 



Fig. 38. Plant lice, half-winged insects. Cross lines and small figure 

 show natural size. 



that do much damage to grain, especially wheat, barley, 

 oats, and rye. The plant louse or aphis is generally green 

 or black, sometimes yellow ; in fact if we observe closely 

 and frequently we shall come to the conclusion that the 

 color of the aphis is not unlike the color of the leaf, stalk or 

 head that it feeds upon. We notice also that the leaves of 

 plants upon which the aphides are found in large numbers soon 

 curl over and become sickly. If we examine a large plant louse 

 we find that it has a strong beak about one-third the length of 

 its body, so that it is well fitted to pierce through the skin of 

 plants and to suck the sap. They live on liquid food. An- 

 other thing we observe in regard to them is that the lice are 

 found in large numbers, and they multiply very rapidly. Some 

 lice feed largely upon other insects, and are therefore bene- 

 ficial. 



