24 
species are so numerous in these roadside grasses that it would seem 
poor policy to recommend the cutting of the grasses in midsummer 
as a measure of Cephus control. As has been stated, few parasites 
have been found in stems of wheat, but, without doubt, they will 
learn very soon of the presence of Cephus in grain fields and will 
adjust their habits accordingly. 
A braconid, Microbracon ceplii, recently described by Mr. A. B. 
Gahan, 1 also attacks the larvae in grass stems, kills them before 
maturity, and spins a gray parchment -like cocoon within the gallery, 
generally near its lower end. This cocoon is truncate at both ends, 
its disklike extremities completely filling the bore. The adult 
escapes by biting an opening through the stem in the vicinity of the 
cocoon. 
ARTIFICIAL CONTROL 
From the foregoing sketch of the life history of the western grass- 
stem sawfly it seems obvious that this pest will have to be attacked 
while it is in the larval state. The egg and adult stages are both 
brief and are clearly beyond the reach of control measures of any 
sort. For nearly 11 months the insect exists as a helpless larva, 
protected only by the grass or grain stem within which it fives. If 
this stem could be destroyed, the larva within would perish. 
The first remedy that occurs to the farmer or the student of field 
conditions is the burning of the stubble in the autumn or spring. 
It would seem a very simple matter to set fire to the stubble and 
destroy at least the majority of the sawfly larvae that are hibernating 
in it. But when one begins to examine the infested fields it is found 
that the inhabited stems have been cut at the ground level or below 
so that it is often necessary to brush away the earth in order to find 
the stubs containing the larvae. So little heat is generated when 
stubble is burned that these subterranean stems could not possibly 
be harmed by the quick passage of the flames. 
In 1907 Mr. Norman Criddle, in Manitoba, wishing to make a 
thorough test of this particular remedy, spread a layer of straw 
several inches deep over an infested area in a wheat field and set the 
straw on fire. More heat was produced than stubble alone could 
possibly make, the surface of the ground being too warm for the 
hand after the fire had died down. Even after this severe treatment 
it was found that, as far as could be learned by a minute search, 
not a single larva had suffered. They had simply retreated to the 
lower end of the hibernation cell and "kept cool." 
Another fact must be noted in this connection. When a field has 
been damaged seriously by the sawfly, the stubble remaining to feed 
a running fire is of necessity more scanty than in an uninjured field 
1 Gahan, A. B. Description of a new hymcnopterous parasite (Braconidre). In Proo. Ent. Soc. Wash., 
v. 20, no. 1, p. 18-19. Jan., 1918. 
