116 



ON THE LIFE HISTORY OF '^WIREWORMS" 



OF THE GENUS AGRIOTES, ESCH., WITH 



SOME NOTES ON THAT OF ATHOUS HAE- 



M0RRH0WALI8, F. 



PART I. 



By a. W. RYMER ROBERTS, M.A. 

 {Rothamsted Experimental Station.) 



(With 5 Text-figures and Plate IV.) 



INTRODUCTION. 



At the beginning of 1916 the necessity for increased crop production 

 caused by war conditions, with which we had then been faced for some 

 eighteen months, brought forward the constantly recurring " wireworm" 

 problem more acutely than ever. Farmers were being urged to plough 

 up more grass-land for the production of cereals and potatoes ; but the 

 reply constantly met with was that if the grass-land were ploughed up, 

 the farmer had no security of harvesting a crop, owing to the probability 

 that the wireworms, which were supposed to exist in great numbers in 

 all old grass-land, would at once concentrate their attention on the crop 

 as soon as it began to grow. The force of this reply was manifest to 

 those who had had experience with the pests. Our knowledge of the Ufe 

 history, or even of its duration, was incomplete, while it was felt that 

 none of the methods of control usually recommended could be relied 

 upon to form a complete rejoinder to the objection of the farmer to 

 altering his system of cultivation. 



In these circumstances it was decided by the authorities at Rotham- 

 sted to make an attempt to supply some of the missing facts and work 

 was accordingly begun in the same year. 



The present paper represents the results obtained in the biology and 

 life history of Agriotes, while it is hoped in the future to publish those 

 obtained in the internal anatomy of the larva and on the research made 

 to secure an adequate ijisecticide for control purposes. 



Many details are still incompletely known, but as certain points of 



