34 
worm is parasitized, and the insect is so reduced in numbers that it 
does not again become abundant for a number of years, in some 
instances not reappearing for twelve or fourteen years. The action of 
this parasitic fly is assisted by various predaceous beetles, which prey 
upon the larvee. 
THE GRASS WORM, OR FALL ARMY WORM. 
(Laphygma frugiperda 8. & A.) 
This species (fig. 21) resembles the last closely in habit, but is more 
distinctively southern in its range, occurring from New York and 
Illinois southward throughout the Southern States. The fall brood of 
larvee is the one which is usually troublesome, hence its name of fall 
army worm. Itis chiefly destructive to grasses, but occasionally raids 
wheat fields and destroys the young 
winter wheat. The half-grown larvee 
in such instances suddenly appear in 
or migrate into the wheat fields from 
neighboring grass lands and feed on 
the wheat voraciously from the end 
of September until they reach full 
growth, some time about the Ist of 
October. They then enter the ground 
and winter in the chrysalis stage, the 
adults appearing in May. Like the 
true army worm, there are several 
summer broods, and in general habits 
and characteristics the two species F!¢-21.—Fall army worm (Laphygma frugr 
eae perda): a, moth, plain gray form; b, fore- 
are closely similar. Both the moth ying of Prodenintike form: ¢) Taeyaieee 
and the larva are extremely variable ‘ended; .¢, abdominal ‘segment of Jazyay 
: 5 lateral view; e€, pupa, lateral view—d, twice 
as regards colors. The moth is natural size; others enlarged one-fourth 
bluaish-gray -in- color, "with dusky ~Grem Chittenden): 
wing markings, being more mottled than the army-worm moth. The 
larva is very dark brown in color in fall, giving the effect of an almost 
black insect. It is marked with a broad buff band along the sides 
and a narrow yellow line on the back. The under surface is greenish, 
more or less mottled with yellow. 

REMEDIES AND PRECAUTIONS. 
The remedies and precautions suggested in the case of the army 
worm apply equally to this species, which is also probably kept in 
check normally by similar, and often by the same, parasitic enemies. 
THE WHEAT SAWFLIES. 
There are quite a number of sawfly larvee which are occasionally found 
in wheat fields. Most of these have very little economic importance 
132 
