IO SECOND REPORT ON ECONOMIC BIOLOGY. 



loses in length ; when the covering has been fixed to the leaf all round 

 and has acquired consistency, it manages to detach itself from con- 

 nection with it and undergoes its change to the pupa; after six or 

 eight days it emerges as a perfect insect, and then cuts a neat spherical 

 hole in its cocoon and so emerges." 



REMEDIAL MEASURES. 



The food plants such as the Knotted Figwort, etc., should be 

 destroyed. 



As the beetles probably hybernate in hedgeside debris, all such 

 material should be burned. 



The larvae frequently fall from off the underside of the leaves on 

 to the ground ; these might be destroyed, if again found attacking 

 cultivated crops, by scattering soot and lime or Kainit on the surface 

 of the ground. 



THE PIGMY MANGEL BEETLE. 



Atomaria linearis, Stephens. 



This beetle has been received from Shropshire and Cheshire 

 during 1911. 



They feed upon the leaves of the mangel, eating out irregular 

 shaped holes, but this external damage is of little moment, the real 

 and serious damage is that done to the sprouts as the seeds germinate 

 and later to the tap root. 



The life-history is only imperfectly known. 



But few experiments have been made as to preventive or remedial 

 measures. Heavy rolling, so as to form a hard, firm seed-bed, is 

 undoubtedly beneficial. 



Dusting with soot has given fair results, but better have been 

 obtained by hoeing in a heavy dressing of soot around the young 

 plants. 



THE LARGE CABBAGE WHITE BUTTERFLY. 



Pieris brassicae, Linn. 



In my last Report I referred to the plague of this insect in the 

 years 1909 and 1910. During the past year it has been still more 

 plentiful, and favoured by the long and dry summer. 



