PREFACE. 
The season of 1899 was marked by extensive outbreaks of the fall 
army worm {Laphygma frugip&rda S. & A). During that season it 
was as injurious perhaps as any other insect, as it was destructive to a 
much longer list of crop plants and over a vast area of territory ; in short, 
this attack was unprecedented in the insect's history. The species is 
common in most seasons and familiar to practical workers in ento- 
molog3 r and to observing persons interested in agriculture, but, 
although it has been known as injurious for many years, its full his- 
tory has never been investigated in all its details in any single locality, 
nor have any very complete accounts been published concerning it. 
It was hoped during the season of 1900 to ascertain certain points 
as to the insect's life habits and economy that might have a bearing 
upon the practical treatment of the species as it occurs in the field and 
garden. For this reason many facts in relation to its biology learned 
during the season of 1899 were withheld from publication to await 
further observations. The season of 1900 was a disappointment as 
regards opportunity for the study of this insect, it seemingly having 
disappeared, at least as a pest, throughout the country. This experi- 
ence is confirmatory of an opinion, held by the writer for some time 
in regard to this and several other species of similar distribution and 
of probable southern origin, that certain atmospheric and other condi- 
tions destroy them in such great numbers in their more northern range 
during the late fall and in the winter that few of the insects are left to 
propagate the species the following season, and that, when these more 
northern localities become restocked with large numbers of the insects, 
such reproduction has been due mainly to the flight of moths from 
southern localities where these conditions have not prevailed, and 
where they multiply in more nearly normal numbers in swamp land 
and similar locations. 
It is to be regretted that the missing data can not be supplied, as it 
seems unwise to delay the publication of the ascertained facts await- 
ing more favorable conditions for observations which may not again 
offer for a year or two, or perhaps longer. The present account is as 
complete as can well be furnished at this time, and it is presented 
herewith in connection with a report of a similar outbreak of a cut- 
worm Avhich occurred during the season of 1900. That season was 
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