Fifth Annual Report. 15 
Before the bugs of the first brood are all mature, and while 
many of them are even in the larval state, they leave the 
fields of small grain and swarm over into the fields of young 
corn. The mature bugs seldom fly at this time, and this makes 
it possible to easily prevent the bugs from entering the fields 
by the barrier method described later in the report. When 
the bugs are casting their skins they have the habit of gather- 
ing together in piles under clods and fallen corn-stalks, etc., and 
since they cast their skins at four different periods of their life 
and the eggs are laid through a period of 20 days, the bugs may 
be found of all ages in these piles. The bugs in the piles have 
often been mistaken for diseased bugs, and we wish to caution 
our readers against such a mistake. The shade and moisture 
which the bugs seek at this time no doubt aid in softening the 
skins so that they may be more easily broken and cast off, and 
very likely the trampling of the bugs over each other in great 
numbers also assists in the process of moulting. 
The bugs emerge from their skins through a slit down the 
back just behind the head, and when the bug has emerged, the 
empty skin is a complete one.. The slit through which the bug 
has crawled often closes up entirely, and then the skins are 
easily mistaken for dead bugs. Their character may readily be 
determined, however, for if they be taken in the hand and 
gently breathed upon they are blown away because of their ex- 
treme lightness. 
The farmers are often deceived by another habit of the bugs: 
When the bugs first enter the corn they mass upon the first few 
rows. At this time their great number is most striking, but in 
a few days they may scatter widely over the fields, and even 
though they are not being destroyed by disease their numbers 
may appear to be essentially reduced. 
We must repeat what we have said in a previous report, that 
the only certain evidence to the farmer that the bugs are being 
destroyed in his fields by Sporotrichum is the presence of the 
dead bugs covered with the dense white spore-bearing growth . 
of the fungus. The reports of farmers to the Station will be 
greatly enhanced in value if the above sources of error are care- 
fully borne in mind. 
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