19 BULLETIN 1076, U. S. DEPARTMENT OF AGRICULTURE. 
termined by Gahan). The parasitic grubs to the number of about a 
dozen emerge from their host larva shortly before time for the pupa- 
tion of the latter. They then spin a mass of brown silk cocoons so 
tightly compacted that it is difficult even to determine their number. 
This mass is found in the burrow or partially constructed cocoon of. 
the host. In more than one instance adults of this parasite were found 
well within the larval burrow of the host, evidently hunting opportu- 
nities for oviposition, but it is not known just how or at what age the 
host larvee are attacked. 
in three instances Chalcis ovata Say (det. Rohwer) was reared 
from the pupe by the authors. 
The authors found but one case of egg parasitism. One ego mass 
was taken which appeared darker than normal. When retained in a 
vial, part of the eggs hatched normally, but the rest, which had 
meanwhile turned jet black, gave forth adults of Trichogramma 
minutum Riley (det. Gahan), one from each egg. 
SCAVENGERS. 
Very often small dipterous maggots were found in the empty bur. 
rows or feeding on decaying larvee or pupe. A number were reared, 
and two species of flies were obtained, Aphiochaeta chaetoneura 
Malloch (det. Greene), and Hlachiptera nigriceps Loew (det. Al- 
drich). These were undoubtedly scavengers, and nothing was ob- 
served to indicate that they were in any way injurious to sound 
larvee or pupe. They seem to thrive equally well on putrid vege- 
table matter. Coquillett (3) mentions rearing the latter of the two 
species from the same situation many years earlier. 
OTHER ENEMIES. 
A somewhat peculiar catastrophe was found to happen very often 
to the larvee which had prepared their pupation chambers in the 
upper end of the petioles of the floating leaves. Some animal, evi- 
dently, took a bite out of the side of the petiole close under the leaf, 
thereby cutting into the cavity and its occupant. In some such cases 
the cut-out portion of the petiole was left hanging, in others it was 
gone, and often the predator had bitten the petiole entirely off at 
this point. No portion of the larve or pupz was ever found in the 
cavity, and the work was very evidently done intentionally in search 
for the insect. Often uninfested petioles were cut, evidently by 
mistake. The possible authors of the work were (1) ducks, a small 
flock of which frequented the pond; (2) frogs, of which there were 
many, some of them very large; (3) fishes; and (4) turtles. The 
character of the work eliminates the ducks and frogs because their 
jaws are not sufficiently strong to make such clean cuts as these were. 
No direct evidence of the presence of fish was found, and in such 
