12 THE HESSIAN FLY IN THE UNITED STATES. 
The only other means of distribution, and the only one which seems 
a possible basis for its transportation to distant regions, is by the car- 
riage of straw containing the puparia, or "flaxseeds," as they are 
called. Under ordinary conditions it is evident that this straw must 
be transported during the summer-resting period of the insect and 
that puparia retaining their vitality must, in the new location, be 
brought into proper situations to permit the development of pupa* and 
the emergence of adults. The winter "flax seeds," being contained 
within the sheaths of growing plants and below the surface of the 
ground, could not furnish a means of dispersal, as at that time the only 
means of distribution would be the shipment of growing plants and their 
transplanting in a new locality, a process certainly not to be thought 
of as a probable source of dispersal. With ordinary development of 
the summer "flax-seeds" there would appear to be little chance of 
scattering the insect in straw, especially since the great majority of 
these must be in the stubble remaining in the field where they grew. 
It has been proved, however, that the puparia may retain their vitality 
under certain conditions for long periods of time, and certainly those 
which may be high enough to be taken from the field with the straw 
would find most favorable conditions for the retardation of their devel- 
opment so that they might be ready for the completion of their cycle 
when the straw is scattered on moist ground in some other and possi- 
bly far-distant locality. The carriage, then, of puparia in straw used 
for packing and shipped from point to point would seem to be the only 
means available for the wide dispersion of the insect, and it is to this 
method that its dispersal is generally credited. The introduction into 
the United States near Xew York City has as its most probable founda- 
tion the straw used as bedding by the Hessian troops landed during 1776 
and 1777, and while there is lacking positive evidence that the insect 
existed at the point of their starting or even of embarkation, the source 
of straw they might have used and scattered after landing may have 
been in some infested locality, while the argument that the troops 
arrived at a time of year when the insect could not have been trans- 
ported disappears when we recognize the possibilities of retardation 
elsewhere discussed. 
The recent introduction of the insect into New Zealand is believed 
to have been due to the scattering of straw used in the packing of 
merchandise, and while the exact time seems unknown, the certainty 
that the introduction must have been in some such manner shows how 
important is the destruction of such packing material in any country 
where the insect is not present and where grain growing is of any 
consequence. Careful attention to this point may serve to postpone, 
at least for some time, the dispersal of the insect in the wheat-growing 
sections of Oregon, Idaho, Washington, and other points, especially 
where wheat culture is carried on in isolated districts separated from 
other wheat regions by extended ranges of mountains or stretches of 
arid land. 
