BROMELIAD MALARIA — SMITH 



389 



former, with a broadly funnel-shaped tank, averaged 90 times as 

 many mosquito larvae per plant as the latter with its slender-necked 

 vase (Downs and Pittendrigh, 1946). However, before this knowl- 

 edge could be used in a more selective form of removing bromeliads, 

 the breaking of the brittle limbs of the immortelles caused several 

 accidents, so that this line of attack had to be abandoned and another 

 sought. 



The second attack was along chemical lines and proved successful. 

 Because of the peculiar structure of the epiphytic bromeliads it was 

 possible to kill them without injuring the trees on which they grew. 



KEY 



L— I ^OPHELES(K£RTES2lR)SELLRT0f> 



ANOPHELES (KERTESZlfl) HOMUNCULUS 



20 

 FI 



10 

 FT. 



^ 



GEOUND 

 LEVEL, 



6 



MOSQUITOES PER MfiN-HOUS 



Figure 1. — The vertical distribution of Anopheles bellator and Anopheles homunculus in the 

 seasonal forests of Tamana, Trinidad, B. W. I. (After Downs andJPittendrigh, 1946.) 



