100 



between the two was most gratif3'ing. His laboratory records are 

 presented in connection with the lengths of the life cycle on page 97. 



From observrations and breeding experiments there can be no doubt 

 that there are four principal generations each season in northern Texas. 

 Besides these there is a hf th, which is of very small extent, and appears 

 too late to damage cotton to an appreciable extent. 



At Victoria, Tex., about 320 miles south of Paris and in about the 

 latitude of Leesburg, Fla. , the number of annual generations, from all 

 available data, appears to be about six. On the basis of four broods 

 at Paris, six broods at Victoria could reasonably be expected by reason 

 of its more southern location .and consequent longer breeding season. 

 In 1903, and also in 1904, moths were out and ovipositing freely b}^ 

 the 1st of April, and in the fall of the former year, essentially normal, 

 larvas had largely entered the soil for hibernation as pupae by the 

 middle of November. There would thus be a breeding period of 234 

 days, time sufficient for six broods at the average time of 37 days for 

 each generation and a few days over, indicating a partial seventh gen 

 eration, which actually occurs b}^ the emergence of a few moths from 

 late fall pup8B. 



It is considered very probable that in the vicinity of Brownsville, 

 Tex., and extreme southern Florida there may be seven full genera- 

 tions each 3^ear. In the vicinity of Miami, Fla., according to Prof. 

 P. H. Rolfs, complete hibernation probabl}^ does not occur, as he has 

 observed bollworm larvae during the winter months feeding on toma- 

 toes, naturally necessitating more or less activity on the part of the 

 moths during this period. However, according to the gentleman men- 

 tioned, the larvae do not appear in force until along toward May, so it 

 would appear that the bulk of the insects hibernate as pupae. 



It is therefore seen that there may be from four to six annual gen- 

 erations of the bollworm for the cotton belt. It will be remembered 

 that this number agrees exactly with the estimated numbers of gen- 

 erations by other workers. For the extreme southern parts of the 

 United Stated complete hibernation ma}^ or may not occur, depending 

 on local conditions and the character of the season. 



The number of annual generations of the bollworm has been indi- 

 cated with more or less certainty for several localities in the central 

 and more northern States. 



For norjthern Delaware, Professor Sanderson states:" 



In this latitude the moths appear during May and deposit their eggs on corn and 

 other food plants, such as beans. * * * The second brood of moths appears in 

 northern Delaware about the middle of July, and a third brood during the first two 

 weeks of September. This would indicate three generations of larvse, the third 

 pupating for the winter. 



"Insects injurious to staple crops, 1902, p. 153. 



i 



