THE MELON" FLY. 7 
established and serious pest throughout all the coastal regions. It 
has been known even to attack cucumbers and squash at altitudes 
ranging up to 4,000 or 4,500 feet. 
METHODS OF SPREAD. 
The melon fly probably is carried more often from one locality 
or country to another in the larva stage than in any other form. 
Quarantine officials at San Francisco have found living larvae in 
host fruits arriving at San Francisco on ships from Honolulu, and 
records prove that the melon fly in the larva stage is able to bridge 
the six or seven days required by the slower vessels to cover the 2,000 
miles between the Hawaiian Islands and California, since infested 
fruits have been intercepted and condemned at least once a year 
since 1912. Host fruits taken on board ships as ship's stores are 
capable of carrying the melon fly as larvae, or later as pupae, in the 
fruit containers, for voyages occupying a longer time than is re- 
quired to cross the Pacific Ocean, and thus may become a factor in 
spreading the pest through vessels plying between almost all coun- 
tries where climatic conditions are favorable for the establishment 
of the fly. 
The spread from one country to another at a considerable distance 
probably starts with the fly in the larva stage, but the spread from 
town to town, or over short distances, as between islands of the 
Hawaiian group, may occur in the adult or pupa stage. A female fly 
has been observed to alight on an automobile top and be carried 16 
miles from the country into the city of Honolulu. On another occa- 
sion an adult was seen flying about an interisland boat en route from 
Honolulu to Hilo, on the island of Hawaii. This fly was not observed 
after the boat weighed anchor at the port of Lahaina, on the island 
of Maui, or 72 miles from Honolulu. These two instances will ex- 
plain the spread of the pest, in the adult stage, about the islands of 
Hawaii, even if it could not be transported in the larva stage. 
When larvae form their puparia on bare surfaces, and particularly 
on a cloth surface, the puparia may adhere sufficiently well to make 
it possible for them to be transported considerable distances under 
favorable circumstances. Although no definite instances are known 
where the melon fly has been spread thus, distribution in this fashion 
is quite feasible and to be expected. 
ECONOMIC IMPORTANCE. 
The melon fly is the most important pest of varieties of melons, 
squashes, and curcurbits in general grown in the Hawaiian Islands, 
and probably elsewhere. Its persistent attack has caused many per- 
sons to abandon the growing of the more susceptible host fruits. 
