2 Trefacc, 



The investigation of the habits and life-histories of the various 

 insects, ineluding the whole practical side of the question, has had to be 

 confined to what could be ascertained, without leaving the Maseunij from 

 specimens and reports furnished by planters and other residents in the 

 localities affected. This method of inquiry was very desirable in the 

 first instance in order to ascertain the nature and seope of the outbreaks 

 which would require investigation. It has been only an initial step, 

 however, and taken by itself is necessarily inadequate. The cordial co- 

 operation of many of those concerned, who have not only made observa- 

 tions tbemselves upon the lines suggested to them, but frequently 

 forwarded living specimens in such cmidition that they could be kept 

 under observulion in rearing-cages in the Indian Museum, has enabled 

 a surprising amount of information to be collected. The limit of useful 

 work to be accomplished through this agency has now been to a large 

 extent attained, and the results arrived at require, for their further 

 elaboration, extensive and prolonged investigations which can only be 

 carried out effectively in the field, where all the concomitant circum- 

 stances can be inquired into. 



The prospect of further advance is a hopeful one, provided means can 

 be found of carrying on the investigation upon a scale commensurate 

 with its importance. Already, the information collected in connection 

 with the habits and life-rhistories of many of the species is sufficient to 

 indicate the possibility of adopting methods or treatment which have 

 done wonders in dealing with correspondiag forms in other parts of the 

 world. Some of these methods have already been experimented itpon 

 with promising results in India, and ase likely eventually to be adopted 

 upon a large scale. Others have been sugi;estedj bnt not yet taken up, 

 while a third class have hitherto hardly so much as reached the ears of 

 the {jreat majority O'f the planting community. 



In particular the insecticides, both liquid and gaseous, and the 

 various forms of ai)paratus for applying ihem, now in general use in the 

 United States, are worthy of special attention, while a fijeld is o-pen for 

 the cultivation of beneficial parasitic forms, seemingly as promisino- as 

 that which has yielded results of the greatest practical value agaiusfe 

 fluted scale in California. 



The only sound basis for investigations directed to the preventioa 

 and mitigation of insect ravages lies in the careful study of the habits 

 and life-histories of the species eoncerned. Kesearches in the field and 

 in the laboratory, however,, must not be divorced from each other, but 

 must go hand in hand, supported by practical experiments upon a scale 

 sufficient to cxclisde error. This has been the system adopted in tlie 

 United States with the result of saving a very appreciable portion of the 

 eaormous diamage previously caused by insect blights ;• and there is no 

 apparent reason why similar procedure in India should not be prodn'.-tivGr 



