1910] Girault and Sanders —Chalcidoid Parasites 155 
ing and its peculiar meconium. Hence, this parasite attacks Phormia 
regina in confinement. 
II. a. On October 1, a pair of adults just reared from Musca 
puparia in horse manure were confined with 40 healthy puparia of 
the same host reared in confinement from maggots in garbage. Ovi- 
position occurred and on October 20 following, four males and 19 
females emerged as the offspring of the single female, making a 
total progeny of 23. 
b. Another pair from the same source and emerging at the same 
time were similarly confined with 30 fresh Musca puparia reared 
from the maggots in garbage. Reproduction occurred and on Octo- 
ber 20, one male and 14 female parasites emerged as the total 
progeny of this pair. 
Hence in confinement, single females were able to kill 23 and 15 
hosts respectively, necessarily laying eggs to the extent of those 
amounts. 
III. A single female parasite captured around the fly cages in the 
insectary, September 10, was confined in a glass vial with 11 healthy 
puparia of Musca domestica reared from maggots in horse manure; 
the parasite was confined with the hosts at 11.50 a. m. the day of 
capture. As a result, on October 1, seven adult females had 
emerged, the total progeny; two of the remaining hosts died but 
examination disclosed no symptoms of parasitism; the other two 
produced 1 ° and 1 * of the host on September 14. 
IV. Eleven females reared from 11 puparia of Musca domestica 
in horse manure September 29-30, and isolated at emergence — 
hence virgin — were separately confined during September 30 with 
single puparia of Phormia regina. Reproduction occurred and in 
three cases single males resulted as the progeny of three of the 
virgin parents; adult hosts emerged in three cases and the remain- 
ing hosts died without showing symptoms of parasitism. Hence 
parthenogenesis occurs with this parasite, the unfertilized ova pro- 
ducing males. Here, there can be no doubt but that the females 
were unfertilized, mating within the puparium, obviously, being 
impossible. 
V. a. September 29, two males and two females of the parasite 
reared from four puparia of Musca domestica on the same day, 
earlier in the morning, were confined with 15 puparia of Phormia 
regina. Oviposition was observed at 11.45 a. m., and doubtless 
