CHAPTER III 

 PLANT-LICE AND GALL-FLIES 



THE minute insects known as " green-fly/' " black-fly/' or 

 collectively as " plant-lice " and " blight," are but too familiar 

 to everyone possessing a garden, however small, while one species, 

 the Phylloxera, is of world- wide notoriety. There are many 

 species of these Afihidce, and they are found in abundance during 

 the summer on rose, cherry, apple and many other trees and 

 shrubs, and likewise on broad-beans, carrot leaves and many 



FIG. 7. Green-fly. 



kinds of " wild plants." They especially frequent the young 

 shoots and leaves, into whose juicy tissues they plunge their 

 piercing proboscis to suck the nourishing sap. Zoologically, 

 they belong to the same subdivision of insects as do the bed- 

 bug, " stinking-bishops," frog-hoppers, cuckoo-spits, scale-insects, 

 mealy-bugs, water-scorpions, water-skaters, and oarsmen. The 

 subdivision is termed " Hemiptera " half -winged, from the 

 fact that many of its examples have the basal part of the fore- 

 wing horny, but the apical membranous, so that the wing appears 

 divided into two halves. The plant-lice, however, are usually 

 found in a wingless condition, and when winged do not exhibit 



