Corn Earworm as an Enemy of Vetch. 13 
The moths conceal themselves among the foliage during the day 
and come out at dusk to lay eggs and to feed upon the nectar and 
sweet juices of various plants. They live about 10 days or two weeks 
and during this time they mate and deposit their quota of eggs for 
the next generation. 
INSECT ENEMIES. 
The corn earworm when feeding on roasting ears or in cotton bolls 
is afforded much protection from its natural enemies. When feeding 
in the open on vetch and other crops it is attacked by numerous para- 
sitic enemies. Chief among these are parasitic flies (fig. 10). These 
flies can be seen flying about 
in the field and depositing 
their eggs on the backs of the 
caterpillars. The eggs are 
whitish, somewhat oval, and 
about the size of a small pin- 
head; they can be seen 
quite readily with the un- 
aided eye. A number of eggs 
may be deposited on the pace 
of one caterpillar. The mag- 
"gots hatching from __ these 
eggs enter the caterpillar’s 
body, feed upon its tissues 
and organs, and gradually 
kill it. When mature the 
maggots leave the body of 
the caterpillar, which often 
has been eaten completely 
with the exception of its  ¥Fic.'10.—Winthemia quadripustulata, a fiy para- 
skin, and enter the ground eucaie pas aN amie Adult. Much en- 
to transform. The skin of 
the maggot hardens into a leathery case, dark red in color, termed a pu- 
parium, within which the tr anwtormation to adult fake place. The 
insect remains in the pupa stage about 10 days and at the end of the 
period the fly emerges. 
These flies make known their presence by their high-pitched, hum- 
ming sound when flying about fields in search of caterpillars upon 
which to place eggs. Among the more important bird enemies of the 
corn earworm are blackbirds, crows, sparrows, bluebirds, and 
meadowlarks. Domestic fowls are usefull’ in reducing the numbers of 
the caterpillars. Toads also devour large nimbers and have been 
found very commonly in vetch fields infested with these caterpillars, 
