Nov. 25, 1918 Biology of Fruit-Fly Parasites in Hawaii 435 



so prolific as are females coming from nonhibernating larvse. The 

 longer the larvae have undergone hibernation, the weaker the repro- 

 ductive system when the female finally emerges. An examination of 

 the ovaries of nine females during 1916 and 1917, originating from 

 larvae hibernating from 3 to 12 months, gave an average of 37 mature 

 eggs per female. Examination of the ovaries of two females originating 

 as larvae that had hibernated 12 months disclosed only 9 and 13 eggs, 

 respectively. Examination of the ovaries of three females maturing 

 from larvae which had lain dormant for 10 months disclosed 31, 10, and 

 24 mature eggs, respectively, 



OVIPOSITION 



The maximum number of eggs usually are deposited during the first 

 week of the life of the female . As many as 30 eggs have been deposited by 

 a single female in a given day. A healthy female usually deposits from 

 5 to 9 eggs daily for the first week and only a few eggs daily thereafter. 

 Death usually follows a few days after the cessation of egg-laying. The 

 largest number of eggs deposited by a female in confinement was 148 

 (Table IV) . This female lived only 1 2 days and died with 54 mature eggs 

 in the ovaries. As noted later, ovipositing females do not live as long as do 

 individuals given no opportunity to oviposit. Only one &gg is deposited at 

 a time. The total operation of laying a single egg requires from 15 to 45 

 seconds after the ovipositor has penetrated the fruit and located a host 

 larva. A female may deposit an egg, rest a moment, and oviposit into the 

 same or another larva immediately, but the ovipositor is completely re- 

 moved after the placing of each egg. In ovipositing, the female moves 

 about over the fruit, frequently pausing and moving in a circle over certain 

 spots. The location of the larva, lying invisible in the fruit, appears to be 

 wholly through a sense of touch. Judging from the actions of the female, 

 all movements over the surface of the fruit indicate attempts to detect vi- 

 brations on the surface due to movements of the larva beneath the skin. 

 When a larva is located, the female elevates the abdomen to an angle of 

 about 45° and the ovipositor is brought to an almost vertical position 

 with the tip resting against the fruit beneath the body. (PI. 32, A.) The 

 parasite never enters a broken fruit or penetrates into exposed pulp 

 containing larvae, all oviposition being entirely from the surface. Upon 

 the insertion of the ovipositor the larva usually attempts to escape and 

 frequently does. Barbs on the end of each of the two sharp, piercing 

 ovipositor blades (fig. 18, c, d) probably enable the female to hold the 

 larva in position, once the blades are fairly inserted. A third blade 

 (fig. 18, 6), which enters with the two piercing blades, but which is not 

 sharp or barbed, is specifically designed for conveying the acid or poison 

 from the acid and alkaline glands (fig. 19, a, h). The head end of this 

 blade bears numerous perforations which are the surface openings of 

 minute branching channels leading from the large central, hollow part of 

 83817°— 18 2 



