The Melon or Bitter Gourd Fruit Fly. 



(PI. II, figs. 6 and 7.) 

 Dacus cucurbitce, Coquillet. 



(Entomological News, May, 1899, pp. 129, 130.) 



The specimens, from which this species was described, were bred from 

 cucumbers in Hawaii, where it is a common and very destructive pest to 

 watermelons, musk melons, cucumbers, tomatoes, and string beans ; but it 

 has never been bred from fruit. At the time it was described its native 

 home was unknown, but subsequently Mr. Muir, of the Sugar Planters' 

 Association laboratories, found that India was its original home ; and my 

 investigations, later on, showed that it was the common Bitter Gourd or 

 Melon Fly, widely distributed over India and Ceylon. 



One of my first investigations in Hawaii was in connection with this pest, 

 and, accompanied by Mr. Van Dine, of the United States Experiment 

 Station, who has written a very concise bulletin, " The Melon Fly," published 

 in The Hawaaian Forestry and Agriculturist (April, 1906, vol. JII, p. 127), 

 I spent several days in the fields and among the melon-growers. Melons are 

 grown under irrigation in large quantities on the rich black soil of Makaha, 

 about 35 miles from Honolulu, where, at Holt's ranch, I obtained many 

 specimens. The work is carried out by Chinese and Japs on the share system, 

 or they rent the land from the owner. The ordinary watermelon, being 

 harder, is not so subject to infestation, after it has reached the size of a hen's 

 egg, as the cantaloupes (rock, melons) ; but as soon as the melon is set, the 

 cultivators place them in paper bags, and thus protect them from the flies, 

 leaving them on the soft-skinned cantaloupes until they are ripe. In conse- 

 quence of the great rise in price of all kinds of melons since the advent of 

 the fly, the growers, under the new methods, may make almost as much 

 money as they did before, but the consumer has often to pay 50 cents for 

 what he used to pay only 10 cents in the old days. 



Where numerous the flies, probably accidentally, puncture the melon stems, 

 and the resulting maggots destroy the tissue, causing much of it to die. 

 Many of the small melons infested were found to be completely hollowed out, 

 and were just a mass of semi-dry pith and maggots, ready to work through 

 the skin and pupate in the ground beneath. Some we found nearly 2 inches 

 below the surface. We found hardly a fly at midday in the melon fields, but 

 on examining the weeds and turnip plants forming a border along the 

 irrigation channels, we found them in numbers resting among the green, 

 foliage. 



At Molokai Island we found some of the growers covering their melon and 

 cucumber beds with cheese cloth, but though it kept the flies out, it also- 

 kept all the bees and small insects that, under ordinary conditions, fertilize 

 the flowers, so that very few melons ever set and matured. 



In spite of the destruction caused by the fruit-flies, with the use of paper 

 bags, Mr. Holt and his Asiatic partners were shipping 800 melons per week 

 to Honolulu, where they brought from 30 to 50 cents a-piece, the picked 

 ones from 75 to 1 dollar each. He works on the halves system, finds the 

 land, quarters, and a mule to cultivate, the men doing all the field work, 

 while he attends to the shipping and sale of the produce. 



