612 
MOTH MILLER 
thread about itself, starting just above the 
head and working backwards more than the 
length of the body. A thin layer of silk 
is spun in the general shape of the cocoon; 
and this framework is covered with fine silk 
from the inside. The larva is able to reverse 
itself within the cocoon, which it does many 
times during its construction. The outer 
layer, upon hardening, becomes very tough 
and even like parchment, while the inner 
layer remains soft and fluffy. Cocoons, both 
whole and broken open, are shown at Plate 
III, below, and in Plate VI, left. The aver¬ 
age time consumed in the construction of the 
cocoon was two and one-fourth days in the 
case of the larvse observed in our cages. 
THE PUPA. 
As the cocoon nears completion, the larva 
becomes very sluggish and the body short¬ 
ens. The last act of the larva is to make 
an incision in the cocoon near the head end 
which provides for an easy emergence of 
the moth at maturity. The average time 
elapsing from the completion of the cOcoon 
to the formation of the pupa was three and 
three-fourths days in the cages of the ex¬ 
periments. 
The change to the pupa takes place during 
the night. The newly formed pupa is white. 
At the end of the first 24 hours it turns to 
a straw color, very light at first, deepening 
slowly. By the end of the fourth day the 
pupa is light brown and this color gradual¬ 
ly deepens, so that by the end of the pupal 
period the insect is a dark brown. (Plate II, 
d.) The male pup* average 14 millimeters 
(about two-thirds of an inch) in length and 
the female pup* 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 aver¬ 
ages two weeks. 
LIFE HISTORY. 
Prom 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 south¬ 
ern 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 larv* do not pupate until late fall. 
There is a decided overlapping of the gen¬ 
erations, which makes it difficult to deter¬ 
mine the exact number of broods a year. At 
almost any time, from early spring until De¬ 
cember, 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 thruout the year without in¬ 
terruption. Usually the winter is passed 
with about one-third of the insects in the 
pupal stage and the remainder in the lar¬ 
val stage. Warm spells during the win¬ 
ter cause some of the moths to emerge from 
their cocoons; in the laboratory many moths 
emerged when the temperature was main¬ 
tained constantly at 60 degrees P. It is 
not unusual 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 become active 
with the rise in temperature. Such moths 
do not reproduce in localities where freez¬ 
ing temperatures are frequent. 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 
26 degrees F. 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. 
natural enemies. 
Of the natural enemies of the bee moth, 
the most important is the honeybee itself. 
It is a well-established fact that if the col¬ 
ony be kept strong, healthy, and with a vig¬ 
orous queen, it will defend itself against 
the bee moth. This is particularly true in 
the case of "Italian” bees. "In the Ohio 
Cultivator for 1849, page 185, Micajah T. 
Johnson says: ‘One thing is certain: if the 
bees, from any cause, should lose their 
queen, and not have means in their power 
of raising another, the miller and the worms 
soon take possession. I believe no hive is 
destroyed by worms while an efficient queen 
remains in it.’ This seems to be the earliest 
published notice of this important fact by 
an American observer.”* 
This fact is of vital importance in the 
fight against the bee moth, for if the pest 
can be kept from its favorite food, control 
measures are made much easier. The fact 
that the bees under natural conditions are 
able to defend themselves should leave the 
problem of control to such means as will de¬ 
stroy the pest in places other than the hives. 
Recently it has been found advantageous 
to introduce Italian blood into the colony, 
as the workers of this race seem to be more 
efficient fighters of the bee moth. In most 
cases this is sufficient for the control of the 
pest in the colonies, but it must be remem¬ 
bered that the colony cannot be kept under 
close observation and maintained at full 
strength unless domiciled in a frame hive. 
* “Langstroth on the Hive and Honeybee,” by 
Chas. Dadant, page 469. 
