132 
The larva has first been observed in spring in the latitude of Ili- 
nois (namely in Maryland) on May 31, and in Virginia June 18. By 
the 19th of July this brood of larvae was largely full grown in 1889, 
larve, pupe, and freshly emerged imagos occurring at that time at 
Jacksonville, in Morgan county, in this State. We have in fact once 
seen a freshly developed beetle of this species July 5, and Webster re- 
ports it as pairing in Central Indiana in July. Dr. Riley seems to have 
found eggs of beetles in his breeding cages July 7, from individuals 
which emerged the day preceding, the larve having originally come 
from Virginia June 18. Garman finds the ovarian eggs of this (?) 
generation mature in Kentucky July 29, these two being as yet the only 
observations on record concerning the egg. 
The pupation of this brood of larve is not, however, altogether ~ 
completed in Illinois before the end of July. Indeed, larve taken the 
20th of August at Champaign, Illinois, in 1889, were possibly of this 
same brood. The beetles have begun to pair again, however, as early as 
August 8 with us, and young root worms, doubtless of a second genera- 
tion, have been collected at Champaign September 6. Garman’s obser- 
vations in Kentucky are not especially different from these, but the 
dates given for Alabama (“Insect Life,” Vol. IV., p. 104) show a much 
earlier start of the species. ‘The active larva is ‘reported as occurring 
there from March to the middle of May, these earler larve beginning 
to pupate certainly by April 30, and to yield the imago May 21. The 
oceurrence in Minnesota of pupe September 3, which gave the imago 
three days afterwards, is a fact which has no special bearing upon this 
life history. 
I need only add that the eggs are placed, either singly or in groups 
of two to twelve or more, according to Riley’s observations, below the 
surface of the soil near the plants, in cracks or immediately about the 
base of the plants. 
NATURAL ENEMIES. 
So far as now known, the most effective natural check on the mul- 
tiplication of this insect is a bacterial parasite (Bacillus rufans) observed 
by me to infest the larva, killing about three fourths of a considera- 
ble collection of these corn root worms brought from Jacksonville July 
19, 1889. We do not yet know what part of the larva is first attacked 
by this Bacillus, but by the time the resulting disease has reached a fa- 
tal stage, it swarms in all the fluids of the root worm, which have be- 
come practically a pure culture of this bacterial species. Infested lar- 
x lose their characteristic yellowish tinge, becoming gray and some- 
Ww age swollen, and after death they change color through pinkish to dull 
dark red, the internal organs breaking up to a fluid pulp, held for a con- 
siderable time in the tough cuticle of the dead larva. The fluids of 
such specimens have a milky appearance in the pale worms and a red- 
dish tint in the others. This last color is due, not to the color of the 
bacilli themselves but to an excreted coloring matter diffused through 
the fluids in which they grow. In artificial cultures, consequently,—a 
number of which I made in 1889,—a similar color is imparted to the 
culture medium, whether this be solid or fluid. 
