44^ Journal of Agricultural Research voi. xv, no. s 



In addition to being especially adapted for propagation in wet areas, 

 this parasite, for some unexplained reason, favors certain fruits harboring 

 the host larvae. It is produced in Honolulu most frequently from fly 

 puparia secured from the loquat {Eriobotrya japonica), bestill (Thevetia 

 neriifolia), French cherry (Eugenia uniflora), coffee, and the fruits of 

 Chrysophyllum monopyrenum. It will frequently attack larvae in these 

 fruits to the almost total exclusion of heavily infested fruits of the 

 kamani that may be growing close by. It particularly favors the loquat. 



Emergence, mating, and oviposition are not different, so far as can be 

 noted, from these habits as described for D. tryoni. No odor is emitted 

 by the male or female. A meconium is discharged immediately after 

 emergence. The females mav reproduce parthenogenetically, the 

 progeny being always males. 



Adults of this species have been kept alive longer than have any of the 

 other parasites. Between December, 1916, and May, 1917, of 235 adults 

 held in confinement in glass tubes and fed honey and water 43 lived over 

 100 days, II lived 120 days or over, i lived for 134 days, and i for 141 

 days. Most of the long-lived individuals were females. Three males 

 lived for 120, 121, and 127 days, respectively. Without food and held 

 in bright light the majority of the adults die in about 55 hours. One 

 male has been kept alive for 103 hours and 2 females for 79 hours. 



The proportion of sexes is more favorable in this species than in the 

 case of either D. tryoni or Opius huniilis. During 191 6 and 1917 a total 

 of 5,528 males and 5,566 females emerged from fruit-fly material collected 

 in the field. 



Of 83,304 fruit-fly larvae secured in Hawaii during 1916, 2.1 per cent 

 were parasitized by D. jullawayi. During 191 7, as determined from col- 

 lections of 72,139 larvae, the parasitism by this species was 7.3 per cent. 



TETRASTICHUS GIFFARDIANUS 



This species was brought to Honolulu from West Africa by Fullaway 

 in October, 191 4. It was collected and colonized in Africa by Fullaway 

 and Bridwell. It soon became largely propagated and widely distrib- 

 uted in the Territory of Hawaii. Though its life cycle is short and its 

 development as rapid as is that of the opiines, its importance as a para- 

 site prior to 1 91 7 was doubtful. During 191 7, however, it had become 

 better established and had increased very considerably the total para- 

 sitism of the fruit fly about Honolulu in fruits having thick pulps, such 

 as oranges, peaches, and guavas. Larvae in these fruits are not easily 

 reached by braconid parasites. It is the most prolific of any of the intro- 

 duced parasites of the fruit fly, and, under favorable host and weather 

 conditions, may multiply enormously in localized spots. Owing to the 

 short life of the adult, the absence of a hibernating form, its small size, 

 and seemingly poor powers of flight, it rapidly drops off in effectiveness 

 as soon as host material becomes scarce within a short radius. 



