22 Texas AGRICULTURAL EXPERIMENT STATIONS. 
that by the end of the pupal period the insect is a dark brown. (Plate 
II, d.)The male pupe average 14 millimeters (about two-thirds of an 
inch) in length and the female pupe are fully 16 millimeters in length. 
A row of spines arises just back of the head and extends to the fifth 
abdominal segment; the body line is somewhat curved downward. The 
time from the formation of the pupa to the emergence of the moth was 
seven and three-fourths days in the cage experiments. 
The total time from the starting of the cocoon to the emergence of the 
moth averages two weeks. 
LIFE HISTORY. 
From the work which we have 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 as large as the first two, due to the fact that some 
of the second brood of larve do not pupate until late fall, There is a 
decided overlapping of the generations, which makes it difficult to deter- 
mine the exact number of broods a year. At most 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 that the life history is short 
and that 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 60 degrees F. It is not un- 
usual to see moths on the windows of the honey house, trying 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 they may have been in hibernation as adults and becom: 
active with the rise in temperature. Such moths do not reproduce in 
localities where freezing temperatures are frequent. Even the most vigor- 
ous moths cannot withstand a freezing temperature for more than three 
days. Moths in well-protected places cart survive an outside temperature 
as low as 26 degrees I’. for as long as five days. The moths are never 
active during the day when the temperature is below 50 degrees F., 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-wintering 
larvee and pup 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 larve. Usually twelve days 
are required for the eggs of this brood to hatch, so by the first of May mest 
of the first brood of larve are out. The larval period of this brood is 
quite long, most of them feeding at least forty-five days before completing 
their growth. A majority of the larve of the generation are teady to 
pupate by the middle of June, but there is a considerable variation in 
the rate of growth, for some of these larvee feed for six weeks longer 
before attaining their full size. The pupation of the first brood takes 
