28 
ANNUAL REPORT OP NEW YORK 
prolific of any insect which has ever been observed. I find it 
commences bearing when it is but three days old, arid produces 
four young daily. Thus the descendants of a single Aphis will, 
in twenty days, amount to upwards of two millions, each day 
increasing their number to almost double what they were the 
day before. This serves to account for the surprising numbers 
which we had of this insect. 
The Aphis was everywhere supposed to be a new insect, and 
one writer went so far as to name and describe it scientifically, 
in full confidence that the world had never before known anything 
like it. My examinations, however, fully assured me that it was 
identical with a species which has long been known in the grain 
fields of Europe. And on my announcing this, the erroneous 
views which one and another were adopting, were speedily aban¬ 
doned. 
Our best European accounts of this insect, however, are very 
imperfect. They only speak of it as occurring in June and July, 
whereas I find it is present on the grain the whole year round. 
And when the grain is but a few inches high, if half a dozen of 
these insects happen to locate themselves on the same plant, they 
suck out its juice to such an extent that the plant withers and 
dies. 
As yet I have never been able to find a male of this species. 
The} 7 are all females. This is proved by placing any one sup¬ 
posed to be a male in a vial; next morning two or three young 
lice are always found in the vial with it. The general habits of 
insects of this kind are well known. The Aphis on the apple 
tree and other fruit trees, when cold weather arrives, give birth 
to males. The sexes then pair, and the female thereupon deposits 
eggs, which remain through the winter to start these insects 
again the following year. I had supposed it would be the same 
with this Aphis on the grain. I thought, when autumn arrived, 
I should meet with males and find eggs dropped on the blades of 
the grain. But there were none. The females and their young 
continued to appear on the grain till the end of the season. 
They are everywhere on the grain now, buried under the snow, 
ready to warm into life and activity again when the spring opens. 
And on grain growing in flower pots, on which I am keeping these 
insects in full activity through the winter to notice what I can of 
their habits, no males have yet appeared. When, and under 
what circumstances this sex will be produced, is a most curious 
