68 



R\TE OF OVIPOSITION. 



Since the period of reijroductive activity of the boll weevil is so 

 long, the rate at which eggs are deposited is a question requiring much 

 time for its determination. There have been found great variations 

 in the rate at diiferent seasons, and it is clear that oviposition is even 

 more strongly influenced by variations in temperature than is feeding. 

 The rate sometimes varies unaccountably and very abruptly with the 

 same female upon succeeding days. No explanation for this has as 

 yet been found. The rate is influenced also by the abundance of 

 clean squares which the weevil can find, so that it is greater in the 

 early season, as the degree of infestation is approaching its limit, than 

 after infestation has reached its maximum. 



Two extended series of observations have been made to determine 

 especially the normal average and the maximum ability of the female. 



AVERAGE. 



Taking first 54 females which had gone through hibernation, we 

 find that they deposited on the average 2^ eggs each daily in the 

 laborator}^, and 4 females which were followed undqr field conditions 

 for a total of 93 " weevil-days " deposited 489 eggs during that time, or 

 at the rate of 51 eggs each per day. Where the rate of activity is so 

 great it is probable that the length of the period would be somewhat, 

 but not proiDortionately, shortened. From many observations made 

 in the field during the beginning of the squaring season it seems prob- 

 able that a rate of 5 eggs a day is not far from the average in tlie field. 



From 27 females of the first generation a laboratory average rate of 

 2^ eggs each daily was obtained. Five females of this generation 

 confined in a cage in the field during the latter j)art of August for a 

 total of 70 " weevil days" deposited an average of 6| eggs per day. 

 This latter rate is far beyond the actual average rate in the field at 

 that period because of the fact that the weevils can not at that time 

 find enough uninfested squares to lead them to deposit so many eggs, 

 but the possibility remains if only squares enough are present. 



A few words must be said in further explanation of the diff'erences 

 which appear between the field and laboratory results. In the case 

 of the laboratory figures the entire oviposition period of each weevil 

 and the entire number of eggs deposited are taken into the account. 

 As there is a gradual increase in the rate of production of eggs after 

 the beginning of deposition and a gradual decrease from the middle 

 of the i^eriod to its end, the general average is much lower than would 

 be that taken at the time of maximum activity. In the case of the 

 field figures a short period only is covered, and all conditions of square 

 supply were such as to stimulate the weevil to its greatest possible 

 activity. 



