3 
considerably during the last year or two and had turned its attention 
to wheat and rye. In 1908 the authors found it in grasses in the 
Willamette Valley in Oregon. ‘In 1909 Prof. H. B. Penhallow, of 
New York City, writing from Sherwood, N. Dak., stated that it 
was damaging from 5 to 25 per cent of the wheat in many fields 
in the Souris Valley, and Mr. R. W. Sharpe, of Fargo, N. Dak., 
reported similar depredations in the Red River Valley. Larve or 
adults have been found in Manitoba, the Dakotas, Nebraska, Kansas 
(probably), Saskatchewan, Montana, Wyoming, Colorado, Oregon, 
Nevada, and California. 
HABITS AND SEASONAL HISTORY. 
In Manitoba, according to Mr. Criddle,* the eggs are laid singly 
by the female sawfly (fig. 1, 6) upon a stem of grass or wheat, not 
far from the head, between June 20 and the second week of July. 
“The larve (fig. 1, ~@) soon hatch and begin to eat down inside the 
stem, usually reaching the ground toward the end of August, at ~ 
which time they mature.” They then cut a horizontal ring on the 
interior of the stem near the surface of the ground so as nearly to 
sever it, after which they close the cavity below smoothly with a plug 
of castings and spin a thin, silken, cylindrical cocoon below the plug 
(fig. 1,¢). The stem usually breaks off neatly at the engraved ring 
during the autumn, but may remain in position until winter and 
possibly longer. ‘In these retreats,” to quote again from Mr. Crid- 
dle, “the larve pass the winter and remain in an active condition 
unchanged until May of the following year, when they turn to pupe, 
and emerge as perfect sawflies toward the end of June, the date vary- 
ing somewhat with the season.” The adults were taken by Doctor 
Fletcher,” July 5, on the flowers of tumbling mustard. 
The injured stem appears discolored between the first and third 
joints and the larva may be seen through the translucent wall of the 
stem where it is eaten thinnest. In the case of wheat, the stalk often 
bends at this point, an inch or two below a joint rather than above 
as in Hessian fly injury, and the head falls to the ground shortly 
before harvest. Dr. J. H. Comstock ¢ found that the European corn 
sawfly, an allied species, did not affect the size of the head or of the 
kernels, but it is well known that grasses have the heads blighted by 
our species, and Professor Penhallow writes that the heads of wheat 
are shrunken owing to the diversion of sap at this critical time. If 
this be generally true, the damage to the crop is much greater than 
has been estimated from the number of fallen heads. Mr. Criddle? 
@Ann. Rep. Exp. Farms Canada f. 1907-8, pp. 191-192, 1909. 
’ Ann. Rep. Exp. Farms Canada f. 1896, pp. 229-230, 1897. 
¢ Bul. 11, Cornell Univ. Agr. Exp. Sta., November, 1889. 
[Cir 1174 
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