574 
Journal of Agricultural Research 
Vol. XXXI, No. 6 
frequently (#, 6 ), and during the last five years in the East Central 
States have constituted the only really serious factor affecting the 
reliability of sowing dates determined by observations over a series 
of years. 
Moreover, in years of moderate infestation, when the wave of 
infestation is on the up-grade, but because of lack of parasites con¬ 
siderable menace exists, it will be extremely difficult, if not entirely 
impracticable, to find enough flaxseeds for examination. In actual 
practice, even in years of heavy infestation, when parasitism has been 
heavy but not sufficiently so to remove the fly menace, considerable 
difficulty has been met in getting satisfactory records, and in some 
cases it was not at all practical to get them. Entirely successful 
cases of emergence have been obtained, but these almost without 
exception, have occurred in regular years when the emergence fitted 
in quite nicely with the established and set series of dates. 
It would seem, therefore, that the practical application of the 
emergence cage to Hessian-fly investigations is confined principally 
to life history and control studies of other than a predictive nature. 
LITERATURE CITED 
(1 ) American Association of Economic Entomologists. 
1925. INDEX TO THE LITERATURE OF AMERICAN ECONOMIC ENTOMOLOGY 
January i, 1905, to December 31, 1924. 3 v. Melrose High¬ 
lands, Mass. 
(2) Cartwright, W. B. 
1923. DELAYED EMERGENCE OF HESSIAN FLY FOR THE FALL OF 1922. 
Jour. Econ. Ent. 16: 432-435. 
(3) Drake, C. J., Fenton, F. A., and Butcher, F. D. 
1923. hessian fly control in iowa. Iowa Agr. Exp. Sta. Circ. 86, 
11 p., illus. 
(4) Gossard, H. A., and Eastwood, G. R. 
1916. county cooperation tq control hessian fly. Ohio Agr. Exp. 
Sta. Mo. Bui. 1: 230-232. 
(5) -and Parks, T. H. 
1921. hessian fly preyention. Jour. Econ. Ent. 14: 53-60. 
(6) Larrimer, W. H. 
1922. AN EXTREME CASE OF DELAYED FALL EMERGENCE OF HESSIAN FLY . 
Ann. Ent. Soc. Amer. 15: 177-180, illus. 
(7) Osborn, H. 
1898. THE HESSIAN FLY IN THE UNITED STATES. U. S. Dept. Agr., Div. 
Ent. Bui. 16, n. s., 58 p., illus. 
(8 ) United States Department of Agriculture, Bureau of Ento¬ 
mology. 
1889-1905. BIBLIOGRAPHY OF THE MORE IMPORTANT CONTRIBUTIONS 
to American economic entomology. 8 pts. Washington, 
D. C. 
