104 



INCREASE IN NUMBERS DURING THE SEASON. 



The comparative difference in numbers between the moths of the 

 first and second generations can be determined in a general way from 

 the tables on oviposition already given, since corn receives practically 

 all the eggs of these generations. It is seen that the second genera- 

 tion lays about forty times as many eggs as the first, and assuming, 

 as seems to be the case, that these moths lay individually many more 

 than the spring moths, it may be said that for every spring moth 

 there are thirty moths in the second generation. This agrees well 

 with observations made in the field. 



Fifteen, or one-half of these moths being females, lay pj'obably about 

 1,100 eggs each. Of these only about one larva in fifteen matures, or 

 about fifteen times as many as there were moths in the second gener- 

 ation. This number is about 1,100. 



Half of these, emerging as female moths of the next generation, will 

 lay in all some 605,000 eggs. Observations show that about one in ten 

 of these eggs, or 60,500, will give rise to destructive larvas. 



Allowing for the probable decimation of 65 per cent by the para- 

 sites and predaceous enemies of the growing bollworms, there still 

 remain some 21,175 larvae of the third generation to mature on cotton 

 for every moth emerging the previous spring. 



This shows the great importance of destroying the larvae of the first 

 generation, as every one of them will average 683 descendants in the 

 late summer capable of completel}^ ruining 78 large cotton plants. 



DO THE ADULTS HIBERNATE? 



The hibernation of the adult bollworm moth has always been an 

 open question, and in order to obtain all possible data bearing evi- 

 dence on this point, Mr. Girault made a trip into southern Texas dur- 

 ing the early part of Februar}^, 1904, with the especial purpose of 

 searching for hibernating individuals. 



At Corpus Christi and Victoria a number of days were spent in 

 examining places where hibernating moths would be apt to hide. 

 These included woodlands surrounding fields, rubbish in corn and 

 cotton fields, barns, outhouses, etc., but not a single bollworm moth 

 was discovered. Fresh growing plants and garden vegetables were 

 searched also and sugaring tried, but with the same result. 



Mr. J. D. Mitchell, of Victoria, believed that he had frequently seen 

 hibernating specimens, but in two cases at least it was found that he 

 had been misled by the close resemblance in color and general appear- 

 ance of Heliophila {Leucania) tmipuncta Haw. and Bemigia rejpanda 

 Fab., to the bollworm moth. 



All laborator}^ experiments bearing on this point also tend to show 

 that while life may be prolonged by subjection to low temperatures, no 



