308 



THE MONTHLY BULLETIN. 



to one dollar for a watermelon. It has been estimated that the loss in the 

 Hawaiian Islands amounts to almost a million dollars annually in tribute to 

 this little fly, or a little over five cents a day for a family of four, on an esti- 

 mated population of 192,000." 



Five cents a day, $1S.25 a year for each family of four, in a country where the 

 production of vegetable crops is merely an incident to the general business of agri- 

 culture! No wonder the quarantine inspectors of California believe in the purpose 

 of their daily work. 



The adult melon fly illustrated in Fig. 107 is a small reddish-yellow fly, with a 

 wasp-like appearance, and probably would not attract the attention of a casual 

 ..I .server among the many flies usually seen in a truck patch in which more or less 

 decaying vegetable matter is customarily found. The melon fly, however, is dis- 

 criminating, and holds no communion with such flies as confine their energies to 

 reducing the rejected remnants of the crop to an inorganic coudition, but, on the 

 contrary, selects the best and freshest specimens in the field for destruction. No one 

 thing made a more profound impression upon the writer during his investigations in 



Fig. 108. — String beans infested with larva? of the melon fly. Taken 

 at quarantine. (Photo by L. A. Whitney.) 



the territory of Hawaii than the sight— in Chinese vegetable gardens at Mokuleia — 

 of the melon flies stinging and apparently depositing eggs in a squash as small as 

 a thumb-nail and from which the blossom had not fallen. What prospect can there be 

 for any remuneration for the labor and cost of planting a crop with a constant 

 repetition of this performance throughout the season? Severin gives the life cycle 

 of the melon fly: minimum 2!) ; maximum 43 days; and records the rearing of 037 

 melon flies from a pumpkin four inches long. 



Fig. 108 is a photograph of two string beans taken from a lot found in the 

 vegetable lockers of the steamship "Siberia" arriving at San Francisco from Hono- 

 lulu on May 12, 191.2. and is typical of the condition of fully 50 per cent of the 

 beans in the lot — seeds and the fleshy parts partly eaten and the interior a mass of 

 black decayed matter in which were hidden from four to nine maggots of the melon 

 fly. A similar condition of infestation is often found in tomatoes, cucumbers and 

 watermelons among the remnants of ship's stores left in lockers of vessels arriving 

 .it San Francisco from Honolulu. The melon fly has not such a large variety of 

 hosts upon which it feeds as does the Mediterranean fruit fly, but when we digest 

 the statistics covering the truck crops produced in California, the recorded list of 

 its hosts is sufficient to set us to thinking. It has been found attacking and render- 

 ing unfit for food purposes muskmelons, green beans, cucumbers, tomatoes, squash, 

 pumpkins, eggplant, watermelon, kohlrabi and luffra. Also, it is on record that this 

 fly has been bred from the fruits of the mango, orange (?) and papaya. 



