A 
= 
stroying it (see fig. 4). Other natural enemies are the larve of cer- 
tain predaceous flies, and the larve and adults of lady-beetles. The 
little wasplike parasite first mentioned, however, is the one that keeps 
the “green bug” down in normal years, and in years when the 
latter is most abundant finally overcomes it, as was the case this year 
in Kansas, North Carolina, and other States in the more northern 
part of the range of the pest. 
Unfortunately this parasitic wasp—as with the other beneficial 
insects—is active only while the temperature is above 56° F., or at 
least 25° above that at which the “ green bug” breeds freely; and 
herein is the whole secret of the irregular disastrous outbreaks of the 
“oreen bug” in grain fields. As accounting for the outbreak this 
vear (1907), the “ green bug ” had had a whole winter and the follow- 
ing late spring in which to breed and multiply unmolested, and it 
accomplished its principal damage, as in Texas and southern Okla- 
homa, before it was warm enough for the 
parasite to increase sufficiently to over- 
come it. 
As further illustrative of the important 
bearing of weather conditions, it is found 
that in the case of the three important 
outbreaks of this insect, namely, for the 
vears 1890, 1901, and 1907, the temperature 
for the first five months of each of these 
years, Including the latter part of winter 
and spring, was above the normal for the 
winter months and below the normal for 
the spring months; in other words, warm 
Fic. 4.—Wingless female of ‘‘green 
bug,’’ containing larva of the : ; 
parasite Lysiphlebustritici. Much winters and cold, late springs. 
Mae pa The little parasitic wasp which is so 
useful in the control of this pest is native to this country, widely 
distributed, and every year does its work with the “ green bug ” and 
with other aphides. It is always present in grain fields, as shown 
by its appearance every year, to war on these pests whenever the 
weather conditions make its breeding and multiplication possible, 
and its rate of breeding is so rapid (there being a generation about 
every ten days) that with a week or two of favorable weather it 
gains control over its host insects and destroys them. 
ALTERNATIVE OR SUMMER FOOD PLANTS. 
In 1890 the writer found that orchard grass (Dactylis glomerata) 
was a common food plant of the * green bug,” but so far this has not 
been found as especially attractive to the pest during summer. 
although Mr. Paul Hayhurst has found it occurring sparingly on this 
[Cir. 93] 
