204 Annals Entomological Society of America [Vol. VII, 
containing the sugar. The mixture was thoroughly agitated 
by pumping the liquid back upon itself with a common, garden, 
brass spray-pump. To kill the enormous numbers of melon 
flies quickly in a badly infested cucurbit field, one ounce of 
a soluable poison such as potassium arsenate or sodium arsenite 
dissolved in a small quantity of water, was added to the solution 
instead of arsenate of lead. The pump was provided with a 
rose, sprinkler nozzle which throws a fine, mist-like spray. 
Shortly after sunrise the insecticide was applied to all of 
the foliage within the pumpkin patch and also to the vegetation 
bordering the same, such as glue bushes, algeroba trees, bananas, 
sunflowers, castor oil beans, weeds and grass. As already 
stated in the discussion of the feeding habits of the adults, the 
pest was found feeding on flowers about a hundred yards away 
from the breeding grounds. To spray all of the feeding grounds 
which often consisted of dense brushes of glue bushes, would be 
practically impossible. The results obtained after spraying 
were rather striking. Before spraying, thousands and thousands 
of melon flies could be found resting on the lower surface of 
the leaves of the sunflower and castor oil plants, but after 
spraying, only here and there could a specimen be found. 
In all probability, these living flies had recently emerged from 
puparia, or came in from the neighboring feeding grounds or 
from surrounding cucurbit fields. The soluble poisons, how- 
ever, burned the foliage and can not be advocated. 
A few days after the application of the first spray, all of 
the pumpkin vines and bean plants 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 
feeding grounds or from the surrounding fields of cucurbits 
could be controlled, 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 with 
the bait, using arsenate of lead, but frequent rains washed 
off the thin film of sugar and left the plants subject to 
the attacks of the pest coming from outside sources. As 
soon as the weather became settled, a fresh application 
of the bait was made to the watermelon plants and sur- 
rounding vegetation, but the tender stems of many of the 
