11 
deposited around the sides of the flower pot (in which the moths 
were) and had the appearance of being interwoven with a cottony 
substance. Some writers, I notice, say that this insect deposits eggs 
near the roots of grass in sacks resembling cotton. Those I noticed 
were not enclosed in a sack.” The writer remarks: “I do not feel 
at all satisfied with these eggs, for I do not know of any Noctuid de¬ 
positing eggs in this manner in a cottony substance; they are always 
laid close together and perfectly uncovered, in irregular patches. 
May these not have been the cocoons of minute ichneumons en¬ 
veloped in their loose silk?” In this suggestion he is most probably 
correct, as we cannot believe they were the eggs of the Army-worm 
moth. 
It was the opinion of Mr. Walsh, that the moths of the Spring/ 
and as he believed only, brood, which come out in .July and August, 
soon afterwards deposit their eggs on the grass, where they remain 
until the following spring before hatching. 
That in the latitude of Southern Illinois and St. Louis, the eggs 
are deposited in the Spring, usually in April, is now positively 
known: First , by the fact that in two if not in three of the Army- 
worm years the moths have been seen in the latter part of March, 
or first of April, in immense numbers in the meadows and elsewhere. 
Second, by the fact that in two instances (one my own observation) 
the worms were observed in April when very young, at most not 
more than a week old. Third, by the observations of Prof. French 
and myself as to the first appearance of the moths in the Spring. 
In 1861, they appeared in the latter part of March; in 1878, first 
were taken April 18; in 1879, April 2; in 1880, April *2. Fourth, 
by the observations of Prof. Riley, who saw the moths in the vicin¬ 
ity of St. Louis in the act of depositing eggs in the open pasture, 
in the early part of April. 
The evidence, therefore, on this point, so far as this latitude is 
concerned, appears to be conclusive. 
Prof. Riley has shown by his experiments, made in 1876, that the 
moths commence laying in confinement in about two weeks after 
issuing from the chrysalis. We may therefore assume that in their 
natural condition they commence to lay in two or three weeks after 
issuing. In order to have a definite time to use in the calculations 
we expect to make, we shall take sixteen days as the average. A 
small error in this respect will not materially affect the result so 
far as our calculations as to the length of the insect’s life is con¬ 
cerned, as what is added to or taken from the time the moth lives 
before depositing, will have to be taken from or added to the time 
the eggs require to hatch; for the reason that from other data we 
can ascertain very nearly the time that elapses from the moment 
the moth appears until the eggs hatch. 
Prof. Piiley found by experiment that the eggs in a uniform tem¬ 
perature of 75° hatched in about ten days. It is probable, there¬ 
fore, that in their natural condition the time required will be about 
two weeks. As the moths were seen here in 1861, in the latter part 
of March, and the worms hatched about the 25th of April, or one 
month after the appearance of the moth, the time required for the 
eggs to hatch must have been at least two weeks, if we suppose the 
moths were observed soon after issuing. Otherwise we must sup- 
