60 THE MEXICAN COTTON-BOLL WEEVIL. 



Table XXII. — Seasonal rate of oviposition of the boll weevil. 



1 Hibernated weevils. 



2 First generation weevils. 



3 Observed for entire oviposition period and used in discussion of fecundity. 



The influence of temperature upon the rate of oviposition may be 

 shown by the following diagram (fig. 6), wliich expresses in a single 

 line the mean number of eggs laid daily at a 

 given temperature. There is, of course, more 

 or less fluctuation from the mean, and it is 

 due mostly to differences in humidity. 



The maximum number of eggs deposited by 

 any weevil in one day has been recorded by 

 Mr. Cushman as 20 at Tallulah, La. At Vic- 

 toria, Tex., Dr. Morrill recorded two weevils 

 to have laid 108 eggs in three days, or at the 

 rate of 18 eggs per day. Dr. Morrill found 

 that the size of weevils did not affect the rate 

 per day, as four very small females laid 761 

 eggs at the rate of 3.3 eggs per day. It will 

 be noticed that this rate is higher than the 

 average of all the records in Table XXII. The 

 number of eggs produced on the first day of 

 oviposition varies from one to seven. About 

 67 per cent of the weevils at Victoria were 

 found to oviposit fewer than three eggs on the 

 first day. 



Fig. 6. — Diagram to illustrate 

 influence of temperature 

 on average rate of oviposi- 

 tion of boll weevil. (Orig- 

 inal.) 



IS THE FECUNDITY OP THE WEEVIL DECREASING? 



In view of the fact that recent observations have shown a decrease 

 in the fecundity of the gipsy moth in Massachusetts, 1 we have 

 selected from the foregoing table (Table XXII) on the seasonal rate 

 of oviposition the rather meager data bearing on the question of 

 whether the fecundity of the boll weevil is decreasing. We find 76 



■ Howard and Flske, Hull. 91, Bur. Ent,, U. S. Dept. Agr., pp. 109, no, 1911. 



