56 
SCREENINGS. 
Corn and Flour Insects, &e. 
Flour Moth, magnified; outline showing nat. size. 
In the summer of 1886, when Hessian Fly attack first appeared in 
this country, one of the first ideas connected with it was—how and 
whence did it come ? Imported straw was obviously a possible means 
of transmission, but long watch carried on in the most careful manner 
at various ports failed to show presence of more than a single “ flax¬ 
seed ” (that is, chrysalis of the Hessian Fly), this adhering to a straw 
from Belgium. 
Another possible method of introduction was transmission in 
chaff and rubbish from foul corn imports, and this probability was 
greatly strengthened when we found that the “ flax-seeds ” were 
detached from the straw in great numbers by our threshing-machines, 
and that, in the process of cleaning the corn, these “ flax-seeds,” or 
chrysalids, were thrown down with the light weed-seeds and rubbish. 
We thus learnt that they could be detached, and thus we arrive at the 
point that where corn is sent over foul, with the chaff, dust, rubbish, 
&c. still in it, to the amount to which it often comes, that it is highly 
probable that if the crop out of which the corn was threshed was 
infested by Hessian Fly, that the infestation will be imported, and will 
be spread abroad by distribution of cheap screenings. 
But beyond what may happen as to introduction of this one special 
crop-pest, in addition to the weevils, beetles, &c., which it has long 
been known infest imported cargoes, as well as granaries on land, it 
appeared that in what may be called the “ crop rubbish ” thus imported 
there was broken straw, masses of caterpillar-workings, and bits of 
broken ears, with other impurities quite suitable for transmitting crop- 
insect infestation, besides other matters, such as ergot, weed-seeds; 
infested crop-seeds, as Maize, Beans, &c. ; besides a large admixture 
of bits of dry dirt and stones, and also some amount of coal, iron, or 
large nails, and wire. 
