MEDITERRANEAN FRUIT FLY IN HAWAII. 45 



only 1 being puncture free. Ten thick-skinned green fruits in the market from 

 Kalauao had an average of 6.2 punctures, with no fruit puncture free; 4 of 6 thin- 

 skinned purple fruits taken from the market were puncture free, the remaining 2 

 fruits having 1 and 3 punctures, respectively. One thick-skinned green fruit picked 

 by the owner and brought to the laboratory as an example of a fine fly-proof variety was 

 found when examined in his presence to contain 230 eggs in 18 punctures. The 

 details of the examinations of many hundred individual fruits are on file and open to 

 those desiring further information on the infestation of avocados at the time they are 

 offered for sale. 



In spite of the frequency of infestation as indicated above, the avocado does not 

 appear to be a very satisfactory host for C. capitata when one considers its relatively 

 large size and the number of adult flies that can be reared from it. The larval 

 mortality is greater than in many preferred hosts. From thin-skinned purple fruits 

 containing 119, 41, 29, 19, and 37 punctures, 4, 7, 39, 6, and adults were reared. Only 

 36 adults were reared from a green-skinned variety known to have contained 230 eggs. 

 From 1 fruit that had begun to wither on the tree, an unusual occurrence, 16 adults 

 were reared. Forty-eight is the largest number of adults ever reared from a single 

 fruit by the writers. Of 81 fruits of all varieties known to have been infested when 

 placed separately in jars over sand, 39 produced no adults, while from the remaining 

 42 fruits 570 adults were reared. No adults were reared from 427 fruits gathered pro- 

 miscuously and placed in jars without examination to prove them infested. 



54. Date P alm (Phoenix dactylij 'era). 



Although thousands, of fruits of the unimproved date palm (Phoenix dactylifera) 

 ripen each year in Hawaii, the writers have found only one instance of infestation. 

 Thirty-five green, but well-grown, dates collected August 11, 1913, at Ainahau, 

 Waikiki, which appeared to have been affected by some disease that rendered them 

 abnormally moist, yielded 2 adults of C. capitata. This was probably a chance 

 infestation. 



55. Strawberry Guava (Psidium cattleyanum). 



The strawberry guava (Psidium cattleyanum) is a preferred host, and the fruits are 

 usually badly infested. From 96 out of 145 fruits picked March 16, 1913, 364 adults 

 were reared, or an average of 3.8 per fruit. No fruit yielded more than 8 adults. From 

 500 fruits an average of 4.1 adults were reared during April, 1913. From 90 fruits 

 collected during February, 1916, an average of 4.8 adults per fruit were reared; 15 

 fruits yielding 1, 3, 2, 11, 7, 7, 6, 5, 9, 7, 6, 2, 8, 6, and 18 adults, respectively. 



56-58. Guavas. 



The common guavas of Hawaii (Psidium guayava, P. guayava pomiferum and P. 

 guayava pyriferum) are subject to general infestation. While the guava grows wild 

 up to 4,000 feet elevation and forms dense thickets on the lower levels, even many 

 miles from habitations (Pis. II, III), and is an ever-present source of adult flies, many 

 statements previously published exaggerate the degree of infestation of individual 

 fruits. The writers have never been able to collect samples of 25 miscellaneous 

 fruits without finding some infestation; 14, 18, 15, 17, 10, 10, 10, 24, 7, 6, 6, and 6 

 fruits collected at 14 places on the windward and leeward sides of Oahu on Sep- 

 tember 9, 1914, yielded respectively 60, 46, 46, 107, 119, 11, 19, 4, 41, 1, and 2 adults. 

 Each of 62 fruits, except 7, picked ripe from bushes at points along the Tantalus 

 Road yielded adults; from 55 fruits 307 adults were reared. During January, 1916, 

 75 per cent of all fruits examined along the same road were found infested. From 

 18 fruits collected May 30, 1913, from bushes near the Libby, McNeil, and Libby 

 Cannery, windward Oahu, at sea level, 423 adults, or an average of 23.5 flies per 

 fruit, were reared. Nine fruits collected between Wahiawa and Haleiwa, Oahu, on 

 January 21, 1912, yielded 96 adults. The writers have never reared more than 34 

 adults from a single fruit. 



