224 HENRY H. P. SEVERIN AND HARRY C. SEVERIN 



difference in the number of Mediterranean fruit flies caught. 

 Five white, three black, one blue and seven orange-colored pans 

 were wired to the branches of orange, lemon, grapefruit and 

 guava trees. From the results of our catches in the various 

 pans, it was evident that the number of fruit flies captured 

 was not influenced by the color of the pans. Moreover, it is 

 highly probable that the sense of smell is the determining factor 

 in attracting these insects to the kerosene. 



In our second experiment we endeavored to ascertain in what 

 particular kind of fruit-bearing tree of an orchard the pest 

 would be captured in largest numbers with the kerosene traps. 

 Accordingly, one pan was wired to the lower branches of a 

 common guave tree (Psidium guayava pomiferum), nine pans 

 were fastened in nine different navel orange trees (Citrus auran- 

 tium), and one pan was placed in a Java plum tree (Syzygium 

 jambolana). All of the pans used in this experiment were enam- 

 eled .white, because most insects caught in the oil were more 

 conspicuous against such a background. The following table 

 shows the number of fruit flies taken at intervals of three to 

 four days for a period of eighteen days in the kerosene traps 

 attached to the three different kinds of fruit trees: 



TABLE 1 



Number of Mediterranean Fruit Flies Captured in Kerosene 

 Traps Placed in Guava, Orange and Plum Trees. 



Trees 



One guava Nine navel orange One Java plum 



Four days catch 75 1155 398 



Four days catch 33 749 207 



Three davs catch 25 715 213 



Three days catch 16 422 60 



Four days catch 35 1093 295 



Eighteen days catch 184 4134 1173 



Average capture per day in 1 



trap 10 25 65 



Total number of males captured 5461 



Total number of females captured 30 



5491 



