1914] Melon Fly, Dacus cucurbitae. 201 
garden. Covering the newly set cucurbits requires constant 
attention and cannot be recommended, if the question of labor 
is taken into consideration. 
£9 Trap crops.—Marsh (9, pp. 155-156) made a test of a 
trap crop by planting cantaloupes among cucumbers. “It 
was thought that the cantaloupes would prove more attractive 
to the flies than cucumbers, but such was not the case, as the 
cucumbers were more badly damaged than the cantaloupes, and 
in the end both crops were practically destroyed by the larve.”’ 
30. Traps——In Honolulu a Japanese glass fly trap is 
used by many of the Oriental merchants to capture house 
flies, blue bottle flies etc.; the insects enter the trap to feed 
and are drowned in soapy water within the apparatus. As 
this trap is similar to our American style of glass fly trap, a 
description of the Oriental type is not necessary. A Japanese 
fly trap with molasses as a bait was wired in a large orange 
tree and in twelve days nineteen male and fifty-eight females 
Mediterranean fruit flies and three male and one female melon 
fly were found drowned in the soapy water. Two of the Ameri- 
can style of glass fly traps with molasses as a bait were placed 
upon the ground in a pumpkin patch but no trypetids were 
caught in these. A dozen of the common, mosquito, screen, 
fly traps with molasses diluted either with water or stale beer 
as a bait were fastened to sticks above the pumpkin vines but 
not a single fly was found in the traps during the five days that 
they were kept in the field. 
31. The use of vegetable, animal and petroleum oils to trap 
the melon flies —Recent investigations have shown that certain 
vegetable and petroleum oils attract enormous numbers of male 
fruit flies of different species. Howlett (7, pp. 412 and 414) found 
that citronella oil has an attraction for the males of the peach 
fruit fly (Dacus zonatus Saund.) and the three-striped fruit 
fly (Dacus diversus Coq.) but the attraction in the last case, 
however, seems perhaps a trifle less powerful than with Dacus 
zonatus. Froggatt (5, pp. 13 and 17) found that the mango 
fruit fly (Dacus ferrugineus Fab.) is also attracted to citronella 
oil but that the melon fly (Dacus cucurbitz Coq.) never came to 
this oil. According to Illingworth (8, p. 160) the apple maggot 
or railroad worm (Rhagoletis pomonella Walsh) avoids citro- 
nella oil. 
