STATE AGRICULTURAL SOCIETY. 35 
to swell and mature them, this insect causes the ripened grain to be more 
or less shrunken and light of weight. 
Rye, however, grows so rapidly and ripens so earty, that it outstrips this 
apis, in its increase, and thus sustains no material injury from it. Winter 
wheat, ripening tnore slowly, experiences more injury. But the crops 
which ripen latest, and when this apis has become multiplied to the great¬ 
est extent, namely, spring wheat and oats, become the most thronged and 
sustain the greatest injury. 
Let us next inquire how it is that this insect is able to become so sud¬ 
denly and so excessively multiplied as we have had it, in the eastern part 
of our State last year, and here in its western part this year. 
I may observe that a hundred years ago it was a current opinion among 
men of science, that certain insects and other creatures pertaining to the 
lower orders of the animal kingdom were generated spontaneously. But, 
more recently, when these instances of supposed spontaneous generation 
came to be closely investigated, one after another of them were found not 
to be such. So that at this day the scientific world wholly discards the 
theory that there is or can be any such thing as spontaneous generation. 
All living things descend from parents; and it is by a pairing of the sexes 
that young are produced and that each species is continued in existence— 
some classes of animals bringing forth their young alive, others laying 
eggs from which their young hatch. 
Insects arc of this latter kind. They are all produced from eggs. But 
in the generation of the plant lice, we meet with one of the most remarka¬ 
ble anomalies which we anywhere find in the works of nature. These 
insects bring forth their young alive, at one time, and they lay eggs at 
another time. All the plant lice which we see upon our fruit trees during 
the spring and summer are females, and these do not produce eggs, but 
living young, which mature in a few days, and (wonderful to tell !) they 
are fertile without any intercourse of the sexes. It is only when cold 
weather and frosty nights arrive, that males are produced. The insects 
then pair, and the females thereupon lay eggs. These eggs remain through 
the winter, to be hatched by the warmth of the following spring. The 
young from these eggs grow up and commence bearing living young, no 
males and no eggs being produced, except as the closing act of their opera¬ 
tions in autumn. 
Such arc the general facts with regard to the generation of the insects 
of this aphis group. And I had supposed it would be the same with this 
grain aphis. Some of you may have been present and heard the remarks 
which I made on this subject at our fair at Watertown a year ago. I 
stated that the eggs of this insect would probably be found late in autumn, 
scattered about upon the leaves of the fall sowed wheat and rye—which 
eggs would hatch with the warmth of the following spring, to start the 
insect upon the grain again this year. But when frosty nights arrived last 
autumn, and when the aphis on the apple trees was found paired, and the 
females were busy depositing their eggs, to my surprise, nothing of this 
kind occurred with this aphis upon the grain. The mature lice continued 
to produce young ones, until they and their young became congealed upon 
the leaves of the young grain by the advancing cold of the season. And 
