149 
ntly necessitate additional food), to devour their excrement once 
twice or even a third time. On the other hand, among grain 
t in the laboratory during the winter, in a favorable temperature 
greater part of the time, I have found kernels containing from 
-fourth to one-third of the substance untouched, together with 
empty chrysalis, showing that the worm had passed through its 
ire transformations and yet had food to spare. 
iter attaining its full growth, the larva withdraws to one side of 
grain, cuts out a disc to provide for the escape of the moth, 
is its cocoon, and either passes the cold season in a torpid state, 
si transforms to the chrysalis at once, as the case may be. 
’he larvae from eggs deposited by the second brood of moths at- 
1 their full growth, or nearly so, before the first cold weather in 
fall, and pass the winter in this stage, either within the cocoon 
before it has been constructed. 
>ut they may winter in almost any stage of their growth, as a 
temperature only causes them to pass into a dormant state, to 
ike and resume work when it rises above 60° Fah. At this tem- 
ature, they mature in about three weeks. When the larva changes 
the chrysalis, its head is at the circular disc which it has prv,- 
usly cut ; the anterior extremity of the chrysalis is also in the 
| ie position, and by the aid of the setae mentioned in the de- 
iption, it pushes against this disc, and finally presses it out and 
lies its escape, leaving the empty shell within. 
’he presence of the insect, either as larva or chrysalis, in the 
f in is not easily detected, the kernels looking as plump and of as 
d color as though they were sound; but in weight their difference 
■ nstantly and strikingly apparent. I found, for instance, that, on 
average, 865 grains of wheat will weigh one ounce, while it re- 
red 1,085 grains of infested wheat, from the same stack, to weigh 
j much,—and this too before the larvae had finished their work. 
*eady method of determining the presence of the pest in grain is, 
place a quantity in water, when the infested grains and those 
cli have been eaten will generally float on the surface. 
SUMMARY OF THE LIFE HISTORY. 
’he insect passes the winter in the larva state, pupates in the 
ing, and the moths appear in May or June. These pair imme- 
fcely, and deposit their eggs on the young grains of the new crop 
the field, if they are allowed to escape, or, if not, on the grain 
the bins where they originated. These eggs hatch in from four 
seven days, and the larvae burrow into the grain and themselves 
isform to moths, about August, or often during the latter part 
uly. These moths pair and deposit their eggs after the manner 
;;he previous brood, and the larvae from these, nearly, if not 
te all, reach maturity during the fall and transform the fol- 
ing spring. The number of broods and time of appearance vary 
fitly, with the climate and season, in warm countries broods fol- 
each other in rapid succession during the entire year. 
—10 
