272 INSECTS INJURIOUS TO STAPLE CROPS. 



edged outwardly with pink. The hind wings are paler in 

 color, crossed in the middle by a slightly darker line." 

 (Howard, I.e.) 



Remedies. — Two points in the life-history of the insect 

 a:£ford oj^portnnity for its control. The first of these is 

 when the young larvae are still in the tips and can easily 

 be crushed by the fingers when tying the vines. ' ' Muffle- 

 heads " should always be picked off and destroyed. 



Early in June when the larvae have left the inside of the 

 vines it is well to remove all the soil from the base of the 

 vine, down to the junction with the old root. The 

 larvae, which will not feed above ground, will go to the 

 old roots^ to which they will do but little injury. The 

 roots should be left thus exposed for about a week. A 

 handful of mixture of coal and wood ashes or ammoniated 

 phosphate should then be applied to each and the plants 

 hilled high. The plant will now send out new rootlets 

 from the main root, and is able to secure necessary nour- 

 ishment through them. 



INJURING THE LEAVES. 



The Hop-louse {Pliorodon liumuli Schr.). 



Like many another aphid the Hop-louse has a most 

 interesting life-history, which has been fully ascertained 

 in but recent years. During the winter the small oval 

 black eggs may be found in the crevices and around the 

 buds of the terminal twigs of plum-trees near infested liop- 

 fields. From these hatch a generation of females, known 

 as '^stem-mothers," during the following spring. The 

 lice of this generation differ in being stouter, with shorter 

 legs and honey-tubes than those of any other generation. 

 Three generations feed upon the plum, the third becoming 



