NO. l8 



SENSE ORGANS OF COLEOPTERA — McINDOO 



39 



(5) Bean foliage sprayed until stveetened arsenicals is more at- 

 tractive than unspraycd foliage. — To ascertain whether the ahove is 

 correct, 16 series of tests were conducted. The arsenicals were pre- 

 pared as stated on the following page, then i gm. of granulated cane 



Table 8. — Tests to determine whether bean foliage sprayed ivith siwetcned 



magnesium arsenate is more attractive to Mexican bean beettes than 



foliage sprayed ivith non-szveetened magnesium arsenate 



sugar or i cc. of a high quality table molasses, corn sirup, and black- 

 strap molasses was added to 25 cc. of the spray mixture (table 6). 



According to the results given in table 6, it is again shown that 

 these beetles like their food sweetened. 



(6) Bean foliage sprayed ivith arsenicals is repellent. — To deter- 

 mine whether bean foliage sprayed with arsenicals is eaten as readily 

 as are unsprayed bean leaves, 24 series of tests were conducted. The 



