146 
PSYCHE 
[December 
c. Ovi position in regard to time. The following time periods for single deposi- 
tions were noted during these observations. 
Deposition number. 
1 . 
2 . 
3. 
4. 
5. 
6. 
7. 
Time, seconds. 
70. 
138. 
96. 
90. 
134. 
85. 
105. 
103, avg. 
7. “ Ejfective” oviposition. The following interesting experiments were per- 
formed to find when, or if ever, there occurred a certain advanced period in the devel- 
opment of the host at which it was immune from the effects of the oviposition of the 
parasite, because of this advanced development. For instance, perfect embryos 
just before exclusion from the egg. Can these be effectually parasitized ? The 
hosts used in these experiments were all deposited in confinement. 
a. On the 26th of September, six hosts showing advanced signs of development, 
were exposed to two females of pretio.m in a small glass vial. They were deposited 
into, and the resulting parasites successfully developed. A check lot of eggs from 
the same source and of the same age, liatcheLl eight (8) hours afterwards. So ovi- 
position was effective up to within eight hours of the exclusion of the host. 
b. Two females and one male of pretiosa issuing from a single ho.st on the 
morning of September 26th, were confined in a small glass vial with a piece of a 
cotton leaf containing four ripe ova of ohsoleta, deposited in confinement, and now 
showing very advanced signs of development. A control lot of hosts present. 
At 10:22 .V. M., pretiosa began to oviposit into the hosts. One of the latter' 
received four (4) of the parasitic eggs, the second, two (2) eggs, and the remaining 
two, an egg each, when at 10: 38 a. m. they were removed to a separate vial by them- 
selves. By 8 P. M. the same day, the hosts were still more developed, the black head 
of the embryo perfectly visible through the shell. On the following morning they 
had not changed, and development had evidently been checked. During late p. m., 
September 28th, they turned completely black from the effects of the parasitization. 
Eight parasites emerged from these four hosts during early October. The control 
lot of hosts hatched at 5:30 p. m., September 26th, or seven (7) hours afterwards. 
Hence, oviposition effective up to within seven hours of exclusion of the host. 
