51 
fined a great many worms for days at a time, not a healthy pupa of 
rapce was formed. 
Neither of these parasites nor any other affected the Plusia in the 
least. 
About August 20 the Plusias began to appear in greater numbers, 
not formidable as yet, but so numerous that I began to collect them in 
separate cages for experiment. From this time on until the 1st of 
October this insect multiplied at an astonishing rate. About the mid- 
dle of September a late bed of cabbage, of x>orhaps a little more than 
one acre, which had almost escaped rapce, was found to be literally alive 
with these larvae, from ten to forty or fifty beiug found on a single 
Xfiant. They destroyed it very rapidly, until the gardener put a man 
under my direction to kill them, which was done very successfully. 
The moth was not observed to move about at all during daytime, but 
was frequently found hidden among the leaves of the xfiant. When 
disturbed it flew rapidly in a zigzag manner and soon alighted. 
It deposits its eggs irregularly over the lower side of the leaf, vary- 
ing from a few in number to twelve or twenty. This habit makes it a 
worse enemy, in my estimation, than rapce, as they dex>osit their eggs 
singly, and never in my observations do they happen to get so many 
on one x>lant as brassicce does. The latter, from my observations, is 
much the more prolific, and is also more hardy. 
THE CORN APHIS. 
(Aphis maidis.) 
The only injury I have ever known to be done by this insect occurred 
this year, about 6 miles northeast of this city. A gentleman xfianted 
his corn earty in May. The weather was quite favorable, and it came 
up pronqfily and looked well for a few days, and then began to turn 
yellow and wither awa} 7 . On examining he found what he rightly 
called a u small louse” in great abundance, and associated with it a 
great many small ants. He could not conclude that the louse was the 
cause of injury, so laid it to the ants. The injury became so great in a 
few days that he concluded to x>lant the field all over again, which he 
did with a two-liorse check-row i>lanter. This planting was taken the 
same as the first, and the field again planted over. This last planting 
was not much injured, and with the remnants of first two xdantings 
made quite a crop. On the 11th of July, being in the neighborhood, 
my attention was called to the field. I still found the Aphis present 
in considerable numbers, but the corn was doing fairly well. A large 
number of iusects were examined, yet none but apterous forms were 
observed. The first field is black-loam bottom-land, extending partly up 
on uxfiand, lying beside a creek of considerable size ; it is well drained, 
and the soil is loose and friable. 
