126 



ORDER HEMIPTERA 



fields, upon which the lice maintain themselves until corn 

 plants are available 



This species appears to become so completely adapted 

 for underground life and the association with ants that it 

 does not necessitate producing any winged generation for 

 distribution or for alternation with another food plant. 



On account of this relation to ants, one of the measures 

 of control is to plow and harrow the ground thoroughly 



Fig. 83. — Woolly aphis {Schizoneura lanigera): a, agamic female; b, 

 larval louse; c, pupa; d, winged female with enlarged antenna above; 

 all greatly enlarged and with waxy excretion removed. (From Marlatt, 

 Div. Ent., U. S. Dept. Ag.) 



in order to break up the nests of the ants. This method 

 adopted in the autumn together with a wider cultivation 

 and destruction of weeds in the fields in spring will assist 

 in keeping the pest in check. Perhaps the most important 

 measure is a rotation of crops so that corn will not be culti- 

 \ated for a number of years in succession on the same ground. 

 Woolly Apple Aphis {Schizoneura lanigera). — The woolly 

 apple aphis is a very destructive species, its injury for the 



