HEMIPTERA: THE TRUE BUGS 



91 



It was formerly supposed that to a large " extent each 

 kind of plant was subject to attack by a special kind of 

 plant louse, but after careful studies were made of the 

 structure and life histories of the plant lice, it was found 

 that very often a single species 

 of the insects may attack sev- 

 eral species of plants. One of 

 the most striking examples of 

 this ability to live upon various 

 host plants is that of the Melon 

 Aphis, which infests an extraor- 

 dinary variety of host plants. 

 These include vegetable, field, 

 and fruit crops, as well as many 

 cultivated flowers and an extraor- 

 dinary number of weeds and 

 other wild plants. It has been 

 known by such common names 

 as Cotton Aphis, Orange Aphis, 

 and Dock Aphis. It is so com- 

 monly destructive to melons, cu- 

 cumbers, and related plants that 

 it is now generally called the 

 Melon Aphis, although in cotton-growing regions it is 

 known as the Cotton Aphis. 



The life history of this insect is not very different from 

 that of the Spring-grain Aphis already described. The 

 winter is passed both in the egg state, and in that of the 

 viviparous females. Reproduction begins early in spring 

 and continues throughout the season, the insects multiply- 

 ing with marvelous rapidity and migrating from time to time 

 from one food plant to another. The ability of the species 

 to develop upon so great a variety of hosts renders it 



