BEHAVIOR OF THE FRUIT FLY 225 



It is evident from this table that the attraction of the Mediter- 

 ranean fruit fly to the kerosene was confined almost entirely to 

 the male sex. Female flies were present in this orchard because 

 hundreds were caught by sweeping with an insect net among 

 the fruit trees. Trapping the pest with kerosene was carried 

 on for a period of eight months in the Hawaiian Islands in con- 

 nection with other experiments and the results show that of 

 every one thousand fruit flies captured only three on an aver- 

 age were females, the remainder being males. 



A dissection of some of the flies captured in the kerosene 

 trap wired to the Java plum tree showed that the alimentary 

 canal was filled with the blue juices of the plum. The ripe plums 

 were seriously infested by the maggots of different species of 

 Drosophilidae and the juices were exuding from the punctured 

 and bruised fruit. Mediterranean fruit flies and some of these 

 plums were placed in a breeding jar and frequently the Trype- 

 tids were seen feeding on the plum juices. The reason why 

 more specimens were captured in the kerosene trap wired to 

 the Java plum tree finds its probable explanation in the fact 

 that the plum is more attractive to the pest then the common 

 guava or navel orange, or possibly because the plum juice was 

 more available than the juices of the less bruised guavas and 

 oranges. 



The Mediterranean fruit fly was often captured in kerosene 

 traps wired to trees that were not bearing fruit and also near 

 fruits in which the pest has not been reported to breed. Kero- 

 sene traps were fastened repeatedly in mango trees (Mangifera 

 indica) months before the mango season was on, and in every 

 instance fruit flies were trapped. One trap was wired in an 

 isolated bread fruit tree (Artocarpus incisa) which at that time 

 bore very hard, green fruit, and in four days twenty-nine male 

 Mediterranean fruit flies were caught. A kerosene trap was 

 also placed in a clump of mulberry shrubs (Morus nigra) bearing 

 ripe fruit, and in four days twelve male flies were taken. In 

 the last catch the flies may have been attracted by the ripe 

 fruit, the juices probably serving as food material for the adults. 

 The interesting part of the last two catches rests in the fact 

 that the pest under consideration does not breed in the fruits 

 of these trees. 



In all probability the reaction of the male Mediterranean 



