ECONOMIC ENTOMOLOGY IX MOCAMBIQUE. 291 



trated our efforts on the direct de'struction of the host, thereby 

 also interfering with the parasite complex and making Natm^e's 

 task more difficult to cope with this same host insect the next 

 season, and involving great expense of funds and energ3^ Now 

 let us begin from the other end, and assist Nature in doing the 

 work of re-establishing the balance. 



There are encouraging signs that this viewpoint is gaining 

 ground. The introduction of parasites into a country where the 

 host has been introduced previously was a step in the right direc- 

 tion, and we all know the striking success achieved in some 

 instances. While not going so far as the late Mr. Craw, of Cali- 

 fornia, in considering the introduction of parasites as a panacea 

 for all our insect troubles, the underlying idea is sound, and I 

 think that a thorough study of the interactions between the 

 various insects will enable us in time to malce better use of the 

 native enemies of our host insect in its control. The work of 

 Mally — the well-known entomologist of the Cape Province — in his 

 endeavours to breed parasites with a grea.ter number of genera- 

 tions per season than normal, thus increasing their effectiveness in 

 the control of the host — may be considered one of the many steps 

 to be taken in this direction towards assisting Nature. 



These matters call for an enormous amount of preliminary 

 investigation, and probably a generation of entomological workers 

 will pass before any really outstanding progress has been made. 

 In the meantime we must continue to employ the old methods, 

 and improve them, never losing sight of the ultimate goal, to let 

 Nature repair where man has put her delicate balance out of 

 joint. No doubt many mistakes will be made, and many efforts 

 will be exerted in vain. However, the only way to achieve 

 success is through a series of failures, and future generations will 

 probably wonder as much at our present complicated system of 

 machinery and chemicals for insect control as they will wonder 

 why we considered it necessary to string miles upon miles of 

 copper wire on poles in order to convey electricity. 



