Nov. 25, 1918 Biology of Fruit-Fly Parasites in Hawaii 



429 



Fig. 14. — Diachasma tryoni: Head of mature larva, dorso-cephalic view. 

 Greatest width 0.50 mm. 



under natural conditions. Thus, in March, 1917, a total of 2,725 French 

 cherries, Eugenia uniflora, collected in Honolulu, 3delded 1,213 puparia 

 parasitized by either Diachasma tryoni or D. fullawayi. One-half of the 

 puparia were placed 

 in glass vials and the 

 remainder in a 

 screened box and cov- 

 ered with j4 inch of 

 sand. Of the lot placed 

 in vials 242, or 39.9 

 per cent, of the larvae 

 of Diachasma s p p . 

 hibernated, and of 

 those in the sand 543, 

 or 89.4 per cent, en- 

 tered hibernation. 

 Again, in September, 

 1 91 7, during a warm 

 part of the year, a 

 quantity of kaniani 

 nuts {Terminalia 

 catappa) was collected in Honolulu and placed in a large screened 

 box containing sand, and left in the open air. Of 785 parasitized 

 fruit-fly puparia forming in the sand in this box 271 produced 



living adults of D. 

 ^"X\ . tryoni in the usual 



time, while the re- 

 maining 514, or 65.5 

 per cent, upon ex- 

 amination late in 

 October were found 

 to contain living 

 larvae of D. tryoni. 

 A repetition of this 

 experiment was 

 started in November, 

 1 91 7. Of 934 para- 

 sitized fruit-fly pu- 

 paria forming in the 

 sand in the box from 

 November 2 to 20, 

 only 69 produced 

 adults of D. tryoni in the usual time. The remaining 865 puparia were 

 opened in January, 191 8, and all were found to contain living larvae of 

 this species. This is an average hibernation of 92.6 per cent and repre- 





Fig. 15. — Diachasma tryoni: Mandible of mature larva. I^ength 0.12 mm. 



