12 



Circular 107 



If, following the spring hatching, there should be sharp cold 

 and freezing weather the starting colonies would be destroyed and 

 the possibilities of an aphis outbreak prevented for the most if not 

 the whole of that season. 



Pig-. 8 



Adult Parasite Laying an Egg in the Louse's Body 

 (After Webster) 



The Parasite's Work 



The parasite's development is completed within the plant louse 

 body, killing the louse. The adult parasite escapes through 

 a circular hole. (Adopted from Webster). 



If the weather shows no sharp cold snaps after the lice hatch 

 but remains cool throughout the spring and early summer, the lice 

 are almost certain to be abundant and reach the proportions of a pest, 



