THE CANADIAN ENTOMOLOGIST 245 



10-14 days is thought advisable. Experience alone will enable us 

 to determine the minimum number of applications necessary to 

 insure good results. 



In the Hawaiian Islands we also obtained good results with the 

 use of the poisoned bait spray to control the Mediterranean fruit 

 fly, even though our experiments were conducted under the most 

 unfavourable weather conditions. In our work, Mally's last for- 

 mula (Table I, 1909), was adopted, but with this difference: Mally 

 used 3 ounces of lead arsenate, and we increased the amount to 5 

 ounces. To check up the effectiveness of the fruit fly remedy in 

 our work 10 kerosene traps were wired in fruit trees located in 

 different parts of a non-isolated orchard containing about 400 trees. 

 The total number of fruit flies captured in these traps in five weeks 

 was 10,239; of this number 10,203 were males and only 36 were 

 females. With the kerosene traps kept in the same trees, the 400 

 fruit trees were sprayed about once a week during the following 

 five weeks. The total number of fruit flies captured in the oil 

 traps in five weeks during and after spraying was 182, of which 93 

 were caught during the first six days. After five applications of 

 the bait, it required a thorough search to find an infested fruit 

 in the orchard, whereas before spraying almost every ripe fruit had 

 been "stung" by the pest. 

 Melon Fly or Bitter Gourd Fruit Fly (Dacus cucurbitce Coq.). 



Marsh (15) tested the poisoned bait spray to control the 

 melon fly in the Hawaiian Islands. His baits were prepared by 

 sweetening water with molasses and adding arsenate of lead or 

 Paris green to the solution. The following proportions of the 

 ingredients were used : 



Molasses 1 qt. 



Paris green M oz. 



Water 1% gall. 



In the experiment with Paris green the applications were made 

 daily, from September 9 until October 14. "Neither the experi- 

 ment with arsenate of lead or with Paris green proved effective. 

 The flies were frequently observed feeding on the poisoned liquids, 

 but evidently did not relish them, and so failed to consume a 

 fatal dose." 



Fuller (5) stationed in Natal, South Africa, used the poisoned 

 bait spray to control the melon fly. He writes: "Where the treat- 



