Insects on the Farm 



159 



insects do not find acceptable food-plants they die. 

 Many insects are exclusively flesh-eating, such as the 

 common "doodle-bugs," wasps, lady-bugs, and many 

 species of wood ants. Mosquitos are a common form 

 of blood-sucking insects. Many parasites are solely 

 responsible for the spread of diseases. The ticks on cattle, 

 which are somewhat related to true insects, are carriers of 

 disease. Cattle do not have the splenic fever (sometimes 

 called Texas fever) except when the germs are carried 

 by ticks that bite them. The 

 common bee lives on the 

 nectar and pollen of flowers. 

 It is not the only insect that 

 lives on nectar. Most species 

 of butterflies, moths, bum- 

 blebees, etc., are nectar- 

 loving insects. We have 

 already learned that these 

 insects are very useful in 

 bringing about the pollina- 

 tion of flowers. 



229. The Feeding Habits 

 of Different Stages. The 

 depredations upon plants 

 and animals are made in 

 various ways. Often the 

 immature stages are more destructive than the adult. 

 Most frequently it is the larval stage (caterpillar, grub, 

 maggot) that depredate upon the plants. The Colorado 

 potato-bug lays its eggs on the leaves. The young larv 

 are hatched out, therefore, right at the breakfast table. 

 In the caterpillar stage, some species of insects occur in 

 great numbers, and they are, hence, often spoken of as 



Fig. 97. Corn ear -worm or cotton 

 boll -worm. After Quaintance. 

 Bureau of Entomology, United 

 States Department of Agricul- 

 ture. 



