MEDITERRANEAN FRUIT FLY IN HAWAII. 33 



become seriously infested unless gathered and sold early. Three grapefruit out of 

 five dropping from the tree in an overripe condition, two months aft^r they had been 

 marked as sufficiently ripe for eating, produced four, two, and four adults. It is 

 interesting to record that when these five fruits were marked they already had been 

 oviposited in. E. M. Ehrhorn reared 16 adults from an overripe grapefruit grown in 

 the Punahou district of Honolulu during November, 1911. The grapefruit grown at 

 ex-Gov. Frear's city and mountain residences have been found infested when much 

 overripe. The fruits used as illustrations (Plate IX) were taken from Tantalus during 

 a particularly wet season when it appeared to the writers that the action of numerous 

 showers had aided the larvae in breaking down the protective rag of the rind. 



The exudation of gum from punctures does not always occur, although at times it 

 may be very excessive in Hawaii. 



24. Shaddock. 



The large, very thick-rinded shaddocks are not infested successfully until they are 

 very much overripe. During March, 1914, fruits were gathered from a tree in Hilo, 

 Hawaii, from which fruits had been taken for the table during the months of January 

 and February. During those months no infestation of the pulp had been noted by 

 the owner. Examinations made of the fag end of the crop showed that larvae had 

 successfully penetrated the pulp and had been able to burrow about through the 

 loose-textured rag. Instances were found in which the larvae had completed their 

 entire development within the rag. As many as 22, 17, 9, 17, 16, 25, 19, 8, 1, and 18 

 living larvae were found in the rag of 10 fruits. Of these 10 fruits only four possessed 

 27, 13, 3, and 12 living larvae in the pulp. On examination, made at the same time, 

 of equally ripe fruits of another shaddock tree that possessed a firmer rag, there were 

 found 6 normal and 39 abnormal appearing eggs; 5, 2, and 3 living larvae in the punc- 

 tures, rag, and pulp, respectively; and 405, 696, and 1 dead larvae in the punctures, 

 rag, and pulp, respectively. 



25. Sweet Oranges. 



Oranges are subject to severe attack from the time they are nearly grown until they 

 fall to the ground or are picked. (See PI. X.) Ten oranges just beginning to turn 

 color, collected in Honolulu in November, 1915, had 14, 33, 74, 4, 22, 13, 99, 11, .20, 

 and 14 punctures, respectively, in their rind; 10 others of another crop gathered dur- 

 ing June, 1913, had 29, 17, 34, 14, 11, 17, 33, 17, 18, and 17 punctures, respectively. 

 Ten ripe fruits picked in the same general locality as these 20 fruits during October, 

 1915, had 21, 2, 17, 10, 10, 3, 2, 46, 9, and 3 punctures, respectively. In spite of the 

 fact that 39 oranges picked in September when they were just becoming well yellowed 

 had an average of 32 punctures per fruit, none of them developed larvae within the 

 pulp. But of 784 oranges gathered during March, 1914, when very much overripe, 

 254 produced 2,272 larvae, or an average of 9 larvae to the fruit. Such data as these, 

 coupled with the more detailed data of Table VIII, throw much light on the wonder- 

 fully resistant power of oranges to fruit-fly attack. Were oranges not so well equipped 

 by nature to withstand attack-they would be ruined long before any of them could 

 ripen. Considering the number of eggs deposited, very few adults emerge even from 

 fruits that become infested in the pulp. Thus, only 5, 13, 4, 1, 6, 12, 6, 30, 8, 4, 1, 1, 

 14, 26, 1, 12, 31, and 2 adults were reared from 18 fruits picked because they appeared 

 to be badly infested. 



26. Sour Oranges. 



The ordinary sour orange commonly found in Florida groves is as severely attacked 

 as is the sweet orange, but on account of the looseness of the rind and rag it becomes 

 infested in the pulp more easily, A larger percentage of fruits become infested in the 

 pulp when well ripened than of sweet oranges. (See Table VIII for data on infest- 

 ation.) 



81340°— 18— Bull. 536 3 



