348 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 6 



which we employed in trapping the pest with kerosene, similar experi- 

 ments were performed by this entomologist. Weinland (1912, p. 

 264) found that "the proportion of females to males caught is about 

 1 to 200." Howlett (1912, p. 413) in experimenting on the effect of 

 oil of citronella on the Trypetid, Dacus zonatus Saund., found that of 

 18,000 specimens captured with this oil, "not more than 50 females 

 were seen, or 0.3 per cent" of the total number of insects caught. 



One would naturally suppose that the destruction of thousands 

 of males in an orchard would soon lead to unfertilized females, for the 

 opportunity that a female would have of copulating under such condi- 

 tions would be greatly reduced. But whether or not a male will 

 copulate more than once has not as yet been proven, nor has it been 

 shown that the eggs of the fruit fly will or will not develop without 

 fertilization. Furthermore, it is not to be inferred that all of the males 

 in the immediate neighborhood of a kerosene trap are caught in a few 

 days, for dozens of them may be captured week after week by sweeping 

 among the leaves of the trees with an insect net. Dewar (1908, 

 p. 3) frequently saw Mediterranean fruit flies around the tin contain- 

 ing the kerosene. Some of the flies would rest on the edge of the tin 

 and later fly away without having touched the oil. "It seems clear 

 that the oil caught only a certain percentage of the flies and that the 

 others continued about the tree as usual." This is an observation 

 which we can confirm. 



Compere, chief quarantine inspector at San Francisco, has kindly 

 given us the following account of the discovery that the Mediterranean 

 fruit fly is attracted to kerosene. At Guilford, Australia, a farmer's 

 wife had prepared some jam and because the ants were numerous 

 around the house, she set the dish containing the jam on a hitching 

 post to cool. To prevent the ants from crawling up to the jam, she 

 daubed kerosene on the post. Towards evening, the daughter, a 

 girl of eight years, noticed that the Mediterranean fruit flies were 

 swarming around the post and she immediately called her mother's 

 attention to this fact. It was thought at first that the fruit flies had 

 been attracted to the jam, but after the father's attention had been 

 called to the matter he investigated and found that the kerosene had 

 attracted the pest. According to the Sydney Morning Herald (1907, 

 p. 645) Devenish who made this discovery, caught 2,000 Mediterranean 

 fruit flies in vessels containing kerosene, in the course of a week in his 

 orchard. According to this account the credit of the discovery that 

 kerosene attracts the Mediterranean fruit fly belongs in part at least 

 to this youthful observer of nature. 



In the further history of the use of kerosene to control the Medi- 

 terranean fruit fly in Australia, it will be seen that this new discovery 



