68 



BULLETIN 536, U. S. DEPARTMENT OF AGRICULTURE. 



on work with over 20,000 adults. During the period May 21 to 28, 



1913, when the daily temperatures ranged between 69° and 82° F., 



with a mean temperature for the period of 76° F., and with a mean 



relative humidity about 66 per cent, many females were not observed 



mating until 7 to 9 days. 



During the period December 14 to 24, 1914, when the weather was 



unusually cool for Honolulu, with the daily temperatures ranging 

 between 61° and 78° F. (a mean for the 

 period about 69.8° F.), and the mean relative 

 humidity about 72 per cent, 1 male was ob- 

 served giving the usual evidences of sexual 

 maturity 8 days after emergence, and several 

 others after 9 days. The first eggs, 3 in 

 number, from about 150 females were ob- 

 tained 8 days after emergence, while 10 and 

 38 eggs, respec- 

 tively, were se- 

 cured after 9 and 

 10 days. Adults 

 emerging on Jan- 

 uary 3, 1916, did 

 not contain well- 

 developed eggs 

 until 10 days later, 

 as shown by daily 



dissections. The temperature during this 



period ranged between 60° and 75° F., 



with a mean of 68.7° F. The .general 



process of egg formation as it takes place 



in the egg tubes is shown in figures 15 and 



16, representing the development of the 



eggs 1, 3, 8, and 10 days after emergence. 



PORTIONS OF PLANT SELECTED. 



Adults of the Mediterranean fruit fly 

 oviposit only in the fruit of the host. The 

 female appears to have no preference for 

 any particular area in the epidermis of 

 very soft fruits, such as the strawberry 

 guava, mock orange, coffee, peach, sapota, or eugeuia, as egg punc- 

 tures are to be found on all portions of the fruit. , But even in these 

 fruits adults oviposit most freely in prematurely ripened areas. In 

 the case of other fruits, the epidermis of which the fly has greater 

 difficulty in puncturing, females are apt to take advantage of previ- 

 ously made abrasions caused by thorn pricks, fungus attack, old egg 

 punctures, etc. Thus the females often deposit eggs in large numbers 



Fig. 15.— Egg tubes of female 

 Mediterranean fruit fly: a, 

 At time of emergence; 6, 3-5 

 days after emergence; during 

 January, 1916. (Original.) 



Fig. 16.— Egg tubes of female Medi- 

 terranean fruit fly: a, Development 

 after 10 days; 6, after 8 days; during 

 January, 1916, at Honolulu. (Origi- 

 nal.) 



