INSECTS. 261 



The scale-bugs and bark-lice (Coccidae) 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. 



ORDER VIII. LEPIDOPTERA (Moths and Butterflies). 



The millers, moths, and butterflies are grouped together 

 as Lepidoptera, and all agree in having four membranous 

 wings covered with dust-like scales, in having a long suck- 

 ing ' tongue' formed of the tw T o maxilla, and in having 

 a complete metamorphosis (p. 241) in which there hatches 

 from the egg a worm-like larva (fig. 80). This stage is 

 commonly known LS a caterpillar or 'worm/ but it differs 

 from all true worms in having legs, and those who wish to 

 call things by their true names should never speak of 

 them as wwms. These larvae always have sharp jaws and 

 simple eyes, and are provided with from eight to sixteen 

 legs. Of these, three pairs are on the thoracic segments, 

 while the abdomen has from one to five pairs. These 

 larvae, when they hatch from the egg, are small, but by 

 feeding they grow, increase in size being rendered possible 

 by frequent molt ings of the skin. At last there comes a 



