SEASONAL HTSTOEY. 



75 



weevils which had become adult about the 1st of August would con- 

 tinue to deposit eggs until the latter part of November. Considering 

 the longest-lived weevils and their last-laid eggs, therefore, it is easily 

 possible for two generations to span the entire year. The weevils 

 developing after the middle of 

 November may go into hiberna- 

 tion, and from their last deposited 

 eggs produce weevils whose last 

 offspring will be ready for success- 

 ful hibernation again. This con- 

 clusion is based upon actual dem- 

 onstration. 



The maximum number of gener- 

 ations will be found by taking the 

 first instead of the last eggs de- 

 posited in each case. In order to 

 ascertain the maximum number of 

 generations which would be pos- 

 sible, the figures for the develop- 

 ment at Victoria, Tex., have been 

 taken. Figure 14 is a diagram 

 which shows the maximum num- 

 ber of generations possible and also 

 the minimum number possible. 

 This is based upon the mean tem- 

 peratures of the various months at 

 Victoria and the known period of 

 development at such mean tem- 

 peratures. The maximum number 

 of generations of course begins with 

 the first egg laid by the first weevil 

 to begin oviposition in the spring 

 and continues with the first egg of 

 the first developing weevil from 

 each generation. In this manner 

 it will be seen that 10 generations 

 are possible for weevils reared on 

 squares. The last egg laid by the 

 first emerged weevil and the last 

 eggs laid by the following genera- 

 tions allow only three generations 

 from the first emerged weevils, 

 which might be considered the 

 minimum. The maximum number 

 of generations from the last emerg- 

 ing weevils by the same system can 

 only be eight generations, whereas 

 the minimum number of genera- 

 tions from the last emerged weevils 

 will be two generations. 



There is no basis for the idea that there is a distinct hibernation 

 brood. The activity of the adults and the development of the imma- 

 ture stages is gradually retarded by the decline in temperature until 



