MEDITERRANEAN FRUIT PLY IN HAWAII. Ill 



During May, 1913, 500, 119, and 331 pupae of all ages were placed in cold storage, 

 the temperature varying from 22° to 24° F. for 5, 7, and 12 days, respectively. After 

 removal to normal temperature all pupae were found to be dead. During July, 1913, 

 2,000 pupae of various ages were subjected to a temperature varying from 24° to 30° 

 F. and averaging about 26° F. for 3 to 16 days; none yielded adults after removal 

 from storage even after only 3 days of refrigeration. On June 24, 1913, 2,500 pupae 

 removed from storage after one month of refrigeration at about 26° F. were found dead. 



Pupae held in refrigeration 4 days at 24° to 30° F. were removed to normal tempera- 

 ture after being held 2 successive days at 33° to 38° F. and 40° to 45° F., respectively, 

 but none yielded adults. 



TRAPS. 



The idea of exposing in infested areas a substance that will attract 

 both sexes of the Mediterranean fruit fly is an excellent one, and may 

 lead to the discovery of some medium which will prove an effective 

 method of control. It was the writers' idea to simulate, in such a 

 substance, the odor emanating from the male C. capitata, but the 

 experiments proved unsuccessful. Severin exposed various oils de- 

 rived from crude petroleum, but found them ineffective. He also 

 used, without satisfactory results, turpentine, coconut oil, citronella, 

 whale and fish oils, vinegar, and vanilla. Hooper in Western Austra- 

 lia experimented with naphtha and turpentine in 1907 without suc- 

 cess, and similar results followed the exposure by Gurney in New 

 South Wales of citronella, linseed, salad, whale, neatsfoot, and fish- 

 oils. Howlett, in India, was able to attract males of Dacus zonatus 

 and D. diversus by exposing citronella oil. Later he believed that 

 he had found the actual substances which are responsible for the 

 attraction of these two species in isoeugenol and methyleugenol. 

 Three traps containing, in the order mentioned, eugenol, methyl- 

 eugenol, and isoeugenol hung in orange trees in a badly infested area 

 of Honolulu captured in 6 days only 2, 10, and 1 male O. capitata, as 

 compared with 77, 153, and 48 males captured in check traps con- 

 taining kerosene hung within 50 feet of them. These three substances 

 were furnished the writers by Severin, who had received them in turn 

 from Howlett. 



Much of the experimental work to which reference has just been 

 made represents but a small amount of that undertaken to determine 

 the effectiveness of traps. It has grown out of the accidental dis- 

 covery in Australia by a housewife that a coating of kerosene oil, put 

 about a post for the protection of a glass of preserves from ants, 

 was attractive to adult C. capitata. This observation led to the 

 heralding, in 1907, of the use of kerosene as a method of control as 

 the "best discovery against the fruit fly in years," and to regulations 

 in Western Australia requiring fruit growers to place from one to 

 two traps in each fruit tree. It is natural that entomologists com- 

 bating this pest should carry on experiments, but the worthlessness 

 of kerosene as a factor of control was not demonstrated until a 

 considerable literature upon the subject had been published. 

 Kerosene is ineffective, inasmuch as it attracts for the most part only 



