THE MONTHLY BULLETIN. 309 



Maggots of the melon By illustrated in Fin:. 100 were first ■ ] < - 1 . . t . ■ . 1 by the horti- 

 cultural quarantine officers of California iu cucumbers found in the steamship 

 "Umatilla" arriving at San Francisco in February, ls!)!>. Tin- latest findings were 

 in cucumbers among the stores of the steamship "Kindjani" arriving at San Fran- 

 cisco from Honolulu on Sunday. .May 20, 1917. During the interim between these 

 two dates detection of this pest in the stores of ships arriving from Hawaiian Terri- 

 tory has been common; yet, nothwithstanding the fact that California is more 



Fig. 109. — Maggots of the melon fly found 

 in cucumbers. Taken at quarantine. (Photo 

 by L. A. Whitney.) 



thoroughly and systematically patrolled and searched by horticultural inspectors 

 than any other agricultural region of a similar area iu the world, no evidence that 

 the melon fly has become established in the state has so far been found or recorded. 

 The authority which forbids the entry of any or all hosts of the melon fly from the 

 territory of Hawaii is found in the provisions of United States Notice of Quarantine 

 No. 13 and in State Quarantine Order No. 4, and the authority to immediately 

 destroy such hosts when brought into the state of California is found in section 5 of 

 the state quarantine law. 



THE MEXICAN ORANGE MAGGOT. 



(Trypeta ludens.) 

 By Avert S. Hott. 



From time to time the fruit growers of this state have had occasion for alarm 

 because. of the damage to similar crops in other sections of the world by insects not 

 known to occur in California. It was because of this dread of serious fruit pests 

 existing in other countries that the horticultural quarantine service in California 

 was created. The next step in the policy of prevention, as indicated by our horti- 

 cultural history, was the investigation to determine the extent of the ravages, the 

 imminence of the danger of the introduction of the causal agent, the methods to 

 prevent such introduction and control measures in the event such a pest should 

 become introduced and established. To attain these aims the records show that it 

 has been found advisable in the past to send experts to foreign countries to conduct 

 such investigations at first hand and to prepare a fund of information which might 

 be readily available should the emergency arise. 



Such an investigation was authorized and conducted for the purpose of providing 

 adequate protection to the fruit industry of California from the Mexican orange 

 maggot. It was to investigate the life history and habits of and the damage caused 

 by this fruit fly that the California State Commissioner of Horticulture sent John 

 Isaac to Mexico on March "2, 1!)05. It is the purpose of this article to explain the 

 reasons for the quarantine against all hosts of this fly rather than to present an 

 account of its natural history. At the same time it is important that no pains be 

 spared to acquaint all who are interested with a general idea of the appearance and 

 habits of this insect. Consequently we offer here only the briefest description taken 

 from Mr. Isaac's report of his trip to the Republic of Mexico. 



The accompanying illustration shows three stages in the developmenf of the 

 Mexican orange maggot. The fly, slightly larger than the house fly. is orange 

 colored with stripes of the same color across the wings. The larva, a maggot, is 

 usually white with a tendency to assume the color of the host. When full grown 

 the maggot is about three-eighths of an inch long, coming to a distinct black point 

 at the head end. Two small black spots, part of the respiratory system, are easily 

 visible at the blunt end. The full-grown maggot leaves the fruit and burrows into 

 the ground where it passes into the adult stage. From thirty to forty-six days are 

 usually required for this transformation. The complete life cycle from the egg to 



