2i8 NATURE-STUDY 



lamb's-quarters weed. The ants climb up the weeds to the 

 colonies of aphides to lick from them the excreted honey-dew. 

 These honey-dew forming plant-lice are sometimes called the 

 ant's cows. Bees and other insects also sometimes drink 

 this liquid. The honey made from this, however, has an 

 inferior and rank quality. 



Plant-lice can weaken or even kill plants by robbing them 

 of their juices, House-plants, such as chrysanthemums, are 

 subject to the attack of these insects and are much injured. 

 The aphides feed chiefly on the stems and leaves, but some of 

 them attack the roots of plants. Garden asters are often 

 killed in this way. The phylloxera is such an aphis, and at 

 one time almost ruined the grape industry of Europe. 



Kerosene emulsion, and fumigation with tobacco and car- 

 bon-bisulphide are common remedies. Soap and sulphur 

 solutions are also used to destroy plant-lice. 



For study, either observe the colonies on different plants 

 outdoors, or bring plants or parts of infested plants to the 

 school. 



Orchards with their sweet-scented, nectar-filled flowers, 

 tender foliage, juicy bark, and luscious fruit always attract 

 many injurious insects. The plant-lice referred to are some- 

 times very troublesome to fruit trees, the apple being especially 

 attacked at the roots. 



Related to the plant-lice are the Bark-lice or Scale Insects, 

 so called from their habit of clinging closely to the tender bark 

 of trees and sucking the juices, also from the scale-like appear- 

 ance of the female insects, which generally are covered with a 

 rounded, protecting scale. We sometimes find upon the 

 leaves of the palm and other greenhouse plants white, flaky 

 spots, which on close examination are seen to be insects called 



