198 ELEMENTS OF COMPARATIVE ZOOLOGY. 



The scale-bugs or bark-lice are also serious pests, doing 

 great damage to fruit-trees, etc. The males are winged, 

 but the female is scale-like and adheres closely to the 

 branch or the fruit, sucking its juices. Oranges and lemons 

 are frequently covered with these forms. A few, however, 

 are of value to man. The pigment carmine is made from 

 the dried bodies (cochineal) of a scale-louse of the cactus, 

 while lac from which shellac is prepared is the secretion 

 of a tropical tree-inhabiting species. 



Besides the Heteroptera and the Homoptera, the Hemip- 

 tera embraces a third division, the PARASITA, or lice. These 

 are all wingless forms, living as parasites in the hair and on 

 the skin of mammals, and sucking the blood of their hosts. 



