269 



FIELD EXPERIMENTS ON THE CHEMOTROPIC 

 RESP(3NSES OF INSECTS. 



By a. D. IMMS, M.A., D.Sc, 



Chief Entomologist, Institute of Plant Pathology, 

 Rothamsted Experimental Station, Harpenden; 



AND 



M. A. HUSAIN, B.A., 

 Government Entomologist, Agricultural College, Lyallpur, Punjab. 



(With 1 Text-figure.) 

 PART I. 



PRELIMINARY EXPERIMENTS. 



PAGE 



2B9 

 271 



277 

 282 

 291 



CONTENTS. 



I. Introductory Remarks 



11. General and Historical 



III. Methods 



IV. Observations conducted at Lymm (Cheshire) 

 V. Bibliography 



I. Introductory Remarks, 



A survey of the literature of applied entomology brings home the fact 

 that the efforts of economic entomologists have been largely confined to 

 the discovery of the means of destroying injurious insects; to studying 

 their life-histories, and to ascertaining the most vulnerable stage thereof 

 for the application of remedial measures. During the last few years 

 artificial means for the destruction of noxious insects have progressed 

 rapidly, and even the comparatively recent methods of combating them 

 by the agencies of parasites have made remarkable advances. In all 

 that has been achieved, however, it is evident that the scientific aspects 

 of investigation have constantly been sacrificed in the interests of results 

 derived by empirical methods. Insecticides are used throughout the 



