246 THE CANADIAN ENTOMOLOGIST. 



ment has been applied for the melon fly which attacks squashes, 

 marrows, pumpkins and the like, it has proved successful." 



We also attempted to control the melon fly with the poisoned 

 bait spray in the Hawaiian Islands. The same formula of the 

 bait which we used to control the Mediterranean fruit fly was 

 adopted to combat the melon fly,* except that 1 ounce of a soluble 

 poison, such as potassium arsenate or sodium arsenite, was added 

 to the solution. As the melon fly feeds during the early morning 

 hours the insecticide was applied shortly after sunrise to all of the 

 foliage within a pumpkin patch, and also to the vegetation bor- 

 dering the same. The results obtained after spraying were rather 

 striking. Before spraying thousands of melon flies could be found 

 resting on the lower surface of the leaves, but several days after 

 spraying only here and there could a specimen be found. In all 

 probability these living flies had recently emerged from puparia, or 

 came infrom the feeding grounds orfromsurroundingcucurbit fields. 



A few days after the application of the first spray all of the 

 infested pumpkin vines were pulled out of the ground and raked 

 together in piles. The infested pumpkins were scattered within 

 these piles and then all was burned. 



To determine whether the melon flies coming from their feed- 

 ing grounds or from surrounding fields of cucurbits could be con- 

 trolled, watermelon seeds were planted in a field adjacent to the 

 former pumpkin patch. The seeds sprouted before we were able 

 to make a vigorous campaign in surrounding cucurbit fields. The 

 watermelon plants were sprayed, but the frequent rains washed off 

 the thin film of sugar and left the plants subject to the attacks 

 of the pests coming from outside sources. As soon as the 

 weather became settled a fresh application of the bait was made to 

 the watermelon plants and surrounding vegetation, but the tender 

 stems of some of the watermelon plants were already infested. 

 Whether the pest, which has been allowed to increase unmolested 

 during the past sixteen years, can be controlled under Hawaiian 

 conditions, when one individual sprays and his neighbours do not, 

 is problematical. In all probability better results could be ob- 

 tained with the poisoned bait spray in a well-isolated cucurbit field 

 away from the valleys, where rains are less frequent during the 

 summer months. (To be continued). 



