30 Texas Ageicultural Experiment Station 



SEASONAL HISTORY 



From the work which was done in trying to identify the different 

 broods or generations of this insect, it appears that there are three 

 broods in the extreme southern part of the United States. The third 

 brood is not nearly so large as the first two, due to the fact that some 

 of the second brood of larvae do not pupate until late fall. There is 

 a decided overlapping of the generations, which makes it difficult to 

 determine the exact number of broods a year. At almost any time, 

 from early spring until December, examination of a colony of bees is 

 likely to reveal this insect in all stages. It is often assumed from this 

 that the life history is short and there are several generations each year. 



In well protected hives the development may continue throughout the 

 year' without interruption. Usually the winter is passed with about 

 one-third of the insects in the pupal stage and the remainder in the 

 larval stage. Warm spells during the winter cause some of the moths 

 to emerge from their cocoons; in the laboratory many moths emerged 

 when the temperature was maintained constantly at sixty degrees F. 

 It is not unusual to see moths on the windows of the honey house, try- 

 ing to escape during the warm spells in December and January. Their 

 presence may be accounted for on the supposition that they have just 

 emerged from their cocoons or that they may have been in hibernation 

 as adults and become active with the rise in temperature. Such moths 

 do not reproduce in localities where freezing temperatures are fre- 

 quent. Even the most vigorous moths cannot withstand a freezing 

 temperature for more than three days. Moths in well protected places 

 can survive an outside temperature as low as twenty-six degrees P. for 

 as long as five days. The moths are never active during the day when 

 the temperature is below fifty degrees P., so at such times reproduction 

 does not take place. 



For College Station, Texas, the following life history and duration 

 of broods has been carefully determined: 



The maximum number of moths which mature from the over-winter- 

 ing larvae and pupae appear about the first of April. These moths are 

 active for some time before any eggs are deposited and it is the middle 

 of April before the eggs _ are laid for the first brood of larvae. Usually 

 twelve days are required for the eggs of this brood to hatch, so that by 

 the first of May most of the first brood of larvae are out. The larval 

 period of this brood is quite long, most of the larvae feeding at least 

 forty-five days before completing their growth. A majority of the 

 larvae of the generation are ready to pupate by the middle of June, but 

 there is a considerable variation in the rate of growth, for some of these 

 larvae feed for six weeks longer before attaining full size. The pupa- 

 tion of the first brood takes place during the last two weeks in June, and 

 by July 1 some of the moths of the second generation a]:e to be seen. 



The moths of this generation emerge at about the same time and 

 give the impression of constituting a very large brood. Most of the 

 eggs are laid very soon after emergence of the moths and by the middle 



