24 BULLETIN 358, U. S. DEPARTMENT OF AGRICULTURE. 



RATE OF OVIPOSITION. 



The rate of oviposition by thirds of the period is shown in Table 

 XIX. From this it is seen that the general average eggs per female 

 per day was the same in the first and second thirds, while in the last 

 it was lower. 



Table XIX. — Rate of oviposition of the boll iveevil obtained in all experiments. 1 





Num- 

 ber 

 of fe- 

 males. 



Season. 



Rate of oviposition. 



Nature of weevils. 



First third 

 of period. 



Second third 

 of period. 



Last third 

 of period. 





Total 

 eggs. 



Daily 

 avg. 



Total 

 eggs. 



Daily 

 avg. 



Total 

 eggs. 



Daily 

 avg. 





19 

 13 

 5 



10 

 19 

 18 

 13 



May to Aug... 

 June to Sept.. 

 July to Sept... 



do.. 



505 

 578 

 152 

 133 



407 

 397 

 289 



2.3 

 2.7 

 4.2 

 1.3 

 1.6 

 1.5 

 2.7 



504 

 692 

 122 

 65 

 379 

 373 

 392 



2.2 

 3.2 

 3.3 

 .6 

 1.4 

 1.4 

 3.5 



387 

 453 

 77 

 46 

 282 

 198 

 275 



1 7 





2 



Second generation grandis 



1.9 



4 





June to Sept.. 

 do 



1 



Male grandis and female thurberiae. . 

 Male thurberiae and female grandis.. 



8 



... do 



2.3 







Total 



2,461 



"2.T 



2,527 



"•2.T 



1,718 











1.4 













i Owing to the fact that the oviposition periods were rarely exactly divisible by 3 it was frequently 

 necessary to allow a difference of a day on one or more of the periods. For this reason the divisors used in 

 computing the final average were slightly different , and consequently the same average per day was secured 

 in the first and second period, though the total eggs were slightly higher in the second period. 



MAXIMUM NUMBER OF EGGS PER DAY. 



The maximum number of eggs deposited by a female in a day was 

 15, this number being deposited on July 17 by a grandis female 

 fertilized by a thurberiae male. This maximum is much lower than 

 the maxima of previous years. The maxima of the various series 

 carried through this year varied from 5 to 15 eggs. 



The record for maximum eggs per day was made at Tallulah in 

 1914 when a first generation female laid 27 eggs. The maximum 

 number of eggs in a day before this time was 26, this record being 

 made by a female at Victoria, Tex., in 1913. 



PERIOD FROM DEPOSITION OF LAST EGG TO DEATH. 



The number of days from the deposition of the last egg to the death 

 of the female varied from 54 days to death on the same day as the 

 last deposition. The average of the 120 weevils observed during 

 the season was 5.8 days. Typical grandis averaged 4.4 days to death, 

 the periods of the individuals varying from none to 13 days. Typical 

 thurberiae averaged 9.7 days, the periods varying from none to 54. 

 Female grandis mated with male thurberiae averaged 2.3 days, the 

 periods varying from none to six, while female thurberiae mated with 

 male grandis averaged 6.2 days, the period varying from none to 24 

 days. 



