TILE MELON FLY IN HAWAII. 51 



Table IX. — Effect of cold-storage temperatures upon the pupw of the melon fly. 1 









Number of pupae y 



ielding adults after removal to normal 



temperature 



Temper- 

 ature of 



Number 

 pupae 

 under 



Age on 

 entering 







after refrigeration for- 











storage 

 room.2 

























observa- 



storage. 



3 



4 



5 



7 



9 



11 



13 



15 



17 



19 



24 





tion. 





days. 



days. 



days. 



days. 



days. 



days. 



days. 



days. 



days. 



days. 



days. 



°F. 





Bays. 

























32° to 33°. . 



425 



2 



7 (100) 













































785 



3 



5(125) 













































1,020 



4 

















































1,945 



5 







1 (245) 









































3,175 



6 

















































2,165 



7 



4 (200) 











































34° to 36°.. 



505 



2 



7(90) 











































640 



3 



5(45) 











































985 



4 



6 (175) 











































2,390 



5 



2 (145) 











































2,104 



6 



3 (195) 











































1,813 



7 



9 (195) 



2 







































36° to 45°.. 



1,975 



6 



21(170) 





12 



3 































1 Numbers in parentheses refer to total numbers of pupae removed after refrigeration 

 for the length of days indicated. 



2 Average, 38° F. 



Submergence in water. — Submergence of host fruits containing the 

 immature stages of fruit flies has been recommended by many writers 

 as an easily available method of controlling these pests. Severin 

 (45) has published the first data on the eifects of submergence upon 

 the melon fly. In his work he submerged beneath 7 inches of dis- 

 tilled water three lots of 100 full-grown larvae which had emerged 

 from their hosts to pupate. One lot was removed after having been 

 submerged 2, 3, and 4 days. After being allowed to dry upon filter 

 paper, 75, 16, and larvae pupated and later yielded 47, 5, and 

 adults, respectively. From these data Severin concluded that sub- 

 mergence of infested vegetables in a barrel or tank of water for a 

 period of 4 days would be sufficient to insure the death of larvae 

 within them. 



Instead of submerging isolated larvae, the writers have submerged 

 infested cucumbers in ordinary tap water at a mean temperature of 

 78° F. The results of daily examination of the larvae within these 

 fruits on submergence from 1 to 6 days are given in Table X. It 

 will be noted that many larvae survive a submergence of 1 and 2 

 days successfully. On the third day but 6 out of 207 larvae in the 

 second and third instars were found living. But 1 out of 374 larvae 

 withstood submergence 4 clays. All of 514 and 773 larvae found 

 in fruits submerged 5 and 6 days were dead. 



Pupae submerged in tap water survived slightly longer than larvae, 

 as indicated by the data in Table XI. Fourteen out of 52 pupae 

 that were from 2 to 4 days old when immersed yielded adults after 

 removal from the water. Only 1 out of 77 pupae of like age sub- 

 merged 5 days survived and yielded an adult, while all of 91 

 submerged 6 days died. The young pupae apparently die more 



