SEASONAL HISTORY. 53 



and that during this period these females deposited an average of 

 nearly 200 eggs. The maximum limits may possibly be considerably 

 higher. In fact, a single union seems to insure the fertility of as 

 many eggs as the average female will lay, and its potency certainly 

 lasts for a period fully equal to the average duration of life. It is 

 probable, however, that there are many cases of repeated fertilization 

 of females. 



PARTHENOGENESIS. 



Several series of experiments were conducted at Dallas, Tex., in 

 August, 1906, to determine whether the boll weevil can reproduce 

 parthenogenetically. Mr. R. A. Cushman kept 24 unfertilized 

 females in confinement for 259 weevil days, and found that they 

 deposited only 43 eggs, all being placed outside of the squares. No 

 fertile eggs were laid. The rate of oviposition was one egg per female 

 every six days. With a similar purpose Dr. Hinds isolated 40 indi- 

 viduals as soon as they matured. 1 Each beetle was supplied daily 

 with fresh, clean squares and careful watch was kept for eggs. The 

 first point noticed was that no eggs were found till the weevils were 

 about twice as old as females usually are when they deposit their first 

 eggs. After they began to oviposit it was found that a very small 

 proportion of the eggs were deposited in the usual manner within 

 sealed cavities in the squares, but nearly all of them had been left on 

 the surface, usually near the opening of an empty egg puncture. 

 This same habit was shown by a number of females, and so can not be 

 ascribed to the possible physical weakness of the individuals tested. 

 The number of eggs deposited was unusually small, and the few placed 

 in sealed cavities failed to hatch. After somewhat more than a 

 month had been passed in isolation a few pairs were mated to see if 

 any change in the manner of oviposition would result. The very 

 next eggs deposited by these fertilized females were placed in the 

 squares and the cavities sealed up in the usual manner, showing that 

 the infertile condition had been the cause of the abnormal manner of 

 oviposition. 



OVIPOSITION. 



AGE AT BEGINNING OF OVIPOSITION. 



As has been shown, normal oviposition never takes place until 

 after fertilization has been accomplished, but it usually begins soon 

 afterwards. Observations upon the age at which the first eggs are 

 deposited can be made more easily and more positively than those 

 upon the age at which fertilization takes place. In a general way, 

 therefore, the observations here given may be cited as also throwing 

 fight upon the time of beginning copulation. Table XIX is intro- 

 duced to summarize the various observations which have been made 

 upon the period preceding oviposition. It will be noticed that the 

 range is from 4 to 14 days during the breeding season. Of course, 

 the weevils which hibernate before ovipositing are not to be consid- 

 ered as of this category. 



1 Bulletin 51, Bureau of Entomology, pp. 91, 92. 



