country, as rapidly as they were settled and wheat became a staple 
article of production. It is periodically abundant; much as most 
other noxious insects are, more abundant some years than others; 
becoming abundant at some localities, and scarce at others. It 
cannot, therefore, truly be said to “migrate” from one part of a 
State to another, or from one natural region to another. * 
Probable limits of the Hessian-fly. — The question naturally arises, 
whether this pest will ever ever infest the wheat regions of Western 
Dakota, Montana, Utah, Colorado, and the Pacific States and ter¬ 
ritories ? We believe not,—though aware that such a statement may 
be hazardous. It was originally an inhabitant of Central and South¬ 
ern Europe; it has become acclimated in the Eastern Atlantic and 
Middle States, in the valley of the Upper Saint Lawrence, and in 
the valley of the Mississippi river ; that it can thrive in the ele¬ 
vated, dry Rocky Mountain plateau region, and withstand the cool 
nights and dry, hot atmosphere of the Far West, seems very doubt¬ 
ful. At least, so slowly has it spread westward, so slight an amount 
of wheat or straw is transported westward, all produce of this kind 
going eastward, that we doubt whether, during this century, at 
least, it will extend west of Kansas and Minnesota, where it has 
already had a foothold for several years. 
SUMMARY OF THE HABITS OF AND REMEDIES AGAINST THE HESSIAN-FLY. 
1. There are two broods of the fly; the first laying their eggs on 
the leaves of the young wheat, from early April till the end of May, 
the time varying with the latitude and weather; the second brood 
appearing during August and the early part of September; and lay¬ 
ing about thirty eggs, on the leaves of the young winter wheat. 
2. The eggs hatch in about four days after they are laid. Sev¬ 
eral of the maggots or larvae make their way down to the sheath¬ 
ing base of the leaf, and remain between the base of the leaves and 
the stem near the roots, causing the stalk to swell and the plant 
to turn yellow and die. By the end of November, or from thirty to 
forty days after the wheat is sown, they assume the “flaxseed” 
state, and may, on removing the lower leaves, be found as little 
brown, oval, cylindrical, smooth bodies, a little smaller than grains 
of rice. They remain in the wheat until during warm weather; in 
April the larva rapidly transforms into the pupa within its flaxseed 
skin, the fly emerging from the flaxseed case about the end of April. 
The eggs laid by this first or spring brood of flies soon hatch; the 
second orood of maggots live but a few weeks, the flaxseed state is 
soon undergone, and the autumn or second brood of flies appear in 
August. (In some cases there may be two autumn broods, the 
earliest August brood giving rise to a third set of flies in Septem¬ 
ber.) 
3. There are several destructive ichneumon parasites of the Hes¬ 
sian-fly, whose combined attacks are supposed at times to destroy 
about nine-tenths of all the flies hatched. Of these, the most im¬ 
portant is the Chalcid four-winged fly (Semiotellus destructor, Plate 
1, fig. i, much enlarged), which infests the flaxseed; and the egg- 
parasite ( Platyyaster , fig. 1). 
