1929] 
Reproduction in Aspidiotus hederx 
233 
In the present case, the work took the following form: 
The stock cultures were derived from oleander plants. 
Larvae that had just escaped from the egg were isolated on 
plants which had been cleaned with great care, and the 
plants were then covered with lamp chimneys whose tops 
were covered with fine meshed gauze. 
Many of the insects were injured in the transfer and died 
within a short time. Some others apparently attached them- 
selves successfully but died during more or less advanced 
instars. Out of 34 larvae that attached themselves after 
isolation only 9 reached the reproductive stage, the deaths 
being distributed approximately evenly over the various 
instars. The host plants used were Aucuba japonica, Hedera 
helix, and an unidentified palm. The offspring of the isolated 
insects were not counted until they themselves had reached 
the adult stage. This was done because of the great dif- 
ficulty of counting the migrating larvae that have just 
hatched and means of course that the number of individuals 
in each brood as here given is not as great as the number of 
eggs or first instars produced by each isolated insect. 
Date of 
Isolation 
Host 
Young first 
appeared 
Number reaching 
adult stage. 
Sex 
1 . 
Oct. 7 
Hedera 
Feb. 1 
12 
Female 
2. 
Oct. 7 
Hedera 
Feb. 3 
28 
Female 
3. 
Oct. 22 
Hedera 
Feb. 10 
10 
Female 
4. 
Oct. 7 
Aucuba 
Jan. 2 
50 
Female 
5. 
Oct. 7 
Aucuba 
Jan. 4 
10 
Female 
6. 
Oct. 7 
Aucuba 
Jan. 8 
24 
Female 
7. 
Oct. 22 
Aucuba 
Jan. 28 
45 
Female 
8.1 
Jan. 10 
Aucuba 
April 1 
52 
Female 
9. 
Oct. 
Palm 
Jan. 15 
9 
Female 
The breeding experiments demonstrate the following 
points: a. The nine isolated individuals as well as all of 
their offspring were females. No males arose on either palm 
or Hedera plants, b. Reproduction occurs without mating, 
regardless of the type of host plant, c. The life cycle is com- 
!This individual was obtained from Experiment No. 4 and thus 
represents a second generation raised under control. 
The temperature of the greenhouse used was very variable, ranging 
from 55° to 90° F. 
