BULLETIN 643, U. S. DEPARTMENT OF AGRICULTURE. 



through the plant tissues. But as the larvae, even when full grown, 

 are only about two-fifths of an inch long, a detailed description of 

 them is of little value. It is enough to know that they differ very 

 little from the ordinary white maggots, of equal size, with which 

 the reader is doubtless familiar. The larva? when full grown leave 

 the host to transform to the pupa stage just beneath the surface of 

 the soil, or beneath any protecting object. They even may transform 

 to the pupa within the host fruit, but this is a rare occurrence. Figure 

 1 shows larvae and pupse about twice natural size. 

 In figure 6 are shown well-grown larvae feeding in 

 the root of a young watermelon plant. Figure 5 

 represents an enlarged larva. 



As the melon fly usually first forces itself upon 

 the attention of the market gardener by the dam- 

 age it does, it is more important to be able to recog- 

 nize it by its work than by a mere description of 

 the different stages. The reader, therefore, is 

 directed particularly to the illustrations, for, be- 

 sides showing types of injury, they make clear 

 that it is in the larva stage that the melon fly 

 causes its greatest damage. 



ORIGIN AND DISTRIBUTION. 



The original home of the melon fly is the Indo- 

 Malayan region. At present it is known to occur 

 in various parts of India, in Ceylon, Java, Macao, 

 Timor, northern Australia, about Singapore, in 

 southern China at Canton and Hongkong, in the 

 Philippine Islands, in Formosa, and in the Ha- 

 waiian Islands. There is some doubt at present 

 about its occurrence at Xagasaki, Japan. 



It is believed that the melon fly was introduced 

 into the Hawaiian Islands at Honolulu from 

 It probably arrived in the larva stage in vege- 

 tables brought along as food from Japan by Japanese coolies emi- 

 grating as steerage passengers to work on the sugar plantations in 

 Hawaii. 



ESTABLISHMENT AND SPREAD IN HAWAII. 



Fig. 3. — The melon 

 fly : a, Eggs de- 

 posited in cavity 

 in young pumpkin 

 flower ; 6, single 

 egg, much en- 

 larged. (Authors' 

 illustration.) 



Japan or China. 



The melon fly was first observed in Hawaii, so far as records show, 

 by Mr. Byron O. Clark, who, during October to December, 1897, 

 found it almost impossible to grow cucumbers, squashes, melons, and 

 similar vegetables in the Kalihi district of Honolulu and about Pearl 

 City. During August, 1398. the pest already was established at Lau- 



