193 



ON THE LIFE HISTORY OF "WIREWORMS" OF 



THE GENUS AGRIOTES, ESCH., WITH SOME NOTES 



ON THAT OF ATHOUS HAEMORRHOIDALIS, F.i 



PART II. 



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



{Zoological Laboratory, Cambridge; lately of 

 Rothamsted Experimental Station.) 



(With 4 Text-figures and Plate IV.) 



EXTERNAL STRUCTURE OF AGRIOTES 0B8CURUS, L. 



The first part of this paper contained an account of the biology and life- 

 history of Agriotes. This part contains descriptions of Agriotes obscurus, L. 

 in the oval, early and late larval stages, together with observations on 

 the pupa. The stages are taken in their natural order, but since an ac- 

 quaintance with the later stages for the sake of brevity has been pre- 

 sumed in describing the early ones, it may perhaps be necessary to refer 

 to the general description of the final instar in some cases. In addition, 

 it has been considered desirable to describe the mouth parts and spiracles 

 of the larva in greater detail than was possible in a general description. 

 Separate sections for each of these have therefore been added. 



In the third part of the paper it is hoped to give some description of 

 the larva of Agriotes sputator, L. with some notes on the early stages of 

 A. sobrinus, Kies. = acuminatus, Steph. and Athous haemorrhoidalis, F. 



I must again express my gratitude to Dr RusseU and the Committee 

 of the Lawes Agricultural Trust for the facilities given me at Rothamsted 

 for carrying on the earlier stages of this part of the investigation, as well 

 as for the figures reproduced in the plate. The later stages have been 

 completed at Cambridge through the kindness of Prof. Stanley Gardiner, 

 to whom my thanks are also due. I wish further to express my indebted- 

 ness to Mr C. Forster Cooper and Dr Hugh Scott for kindly allowing me 

 during the last six months to work in the Cambridge Zoological Museum 

 and to make use of the books and collections there. 



1 A grant in aid of publication has been received for this communication. 



