+ 
as with the other beneficial 
Unfortunately this parasitic wasp 
insects—is active only while the temperature is above 56° F., or at 
be 
least 10° above that at which the * green bug” breeds freely; and 
Fic. 5.—Lysiphlebus tritici, principal parasite of the spring grain-aphis: Adult female 
and antenna of male, greatly enlarged. Egg of Lysiphlebus tritici at right, highly mag- 
nified. (Original.) 
herein is the whole secret of the irregular disastrous outbreaks of the 
“ oreen bug” in grain fields. As accounting for the outbreak in the 
year 1907, the “green bug” had had a 
whole winter and the following late spring 
in which to breed and multiply unmolested, 
and it accomplished its principal damage, 
as in Texas and southern Oklahoma, before 
the weather was warm enough for the para- 
site to increase sufficiently to overcome 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 
Ligeti ok bc eeies Sa COS 1890, 1901, and 1907, the temperature 
"gree bug” containing fOr the first five months of each \oiaiiese 
larva of the parasite Ly years, including the latter part of winter 
siphlebus tritici. Much en- : ‘ : i 
igeed.’. (Onteinal) and spring, was above the normal for the 
winter months and below the normal for the 
spring months; in other words, warm winters and cold, late springs. 
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 
[Cir. 93] 
