27 
now before us. In the calculation made above, giving ninety-five 
to ninety-seven days as the brood period, no account is taken of 
the time the moths live after depositing eggs, and it is limited to 
the Spring brood. 
NUMBER OF BROODS AND HIBERNATION. 
The number of annual broods of this insect has long been, and is 
to a certain extent yet, a disputed point, although now most ento¬ 
mologists—in fact all so far as I am aware—accept the view I first 
advanced in 1861: that in the latitude of Southern Illinois it is at 
least two-brooded. 
In the Prairie Farmer of June 20, 1861, I expressed my belief 
that it is double-brooded, and in that and other articles published 
in the same paper during that year, give my reasons for this opinion. 
In fact, I brought forward absolute evidence of the correctness of 
this opinion, by showing at least one well-attested case of both the 
Spring and Fall broods of the worms appearing in this county the 
same year, in large and injurious numbers. This will be found in 
the Prairie Farmer of August 22, 1861. Afterwards, for a time, I 
was disposed to give way partially to Mr. Walsh’s view, looking upon 
this well-attested case as rather exceptional, or that perhaps the 
species was double-brooded in the southern part of the State and 
single-brooded in the northern portion. This in fact was one of the 
chief points of controversy between Mr. Walsh and myself, as Prof. 
Riley correctly states in his second and eighth reports—Mr. Walsh 
holding that it was single-brooded, while I contended there were two 
generations in a year. I was therefore somewhat surprised to find 
Prof. Riley making the following statement in 1880 (Am. Entomolo¬ 
gist, August, 1880): “From the time Fitch wrote so fully on this 
species, in 1861, until the record of our [Riley’s] observations in 
1875 and 1876, it was the prevailing belief among entomologists that 
there was but one annual brood of the species, especially in the 
Northern States, no absolute evidence of a second brood having been 
obtained.” It is true he says “prevailing belief,” but the omission 
to mention the fact that the point was strongly contested certainly 
conveys a wrong impression. 
It is also evident from Dr. Fitch’s language, and the theory of the 
multiplication advanced by him, that he believed the species to be 
double-brooded. Although he does not expressly say so, Mr. Shurt- 
leff appears to take for granted that such was his belief. Dr. Packard 
appears also to have held the same view in 1861 (Paper in Agl. Surv. 
of Maine), at least in reference to the latitude of Illinois. 
Mr. Kirkpatrick, in the paper already referred to, says: “It is 
not positively known how many broods of Army-worms there are in a 
year, but there is no doubt that there are at least two, for the moths 
hatched in mid-summer deposit their eggs immediately after, and 
the last brood must remain either in the caterpiller or pupa state 
throughout the winter.” 
But what renders this assertion of Prof. Riley the more surpris¬ 
ing is the fact that in 1876 he still believed it to be single-brooded, 
at least in ordinary seasons and north of the 88th parallel, which 
4 
