The Greenhouse Leqf-Tyer 
147 
Aug. 1, 1924 
Longevity 
The adults are relatively long lived, 
their longevity ranging up to a maxi¬ 
mum of 23 days. Out of a total of 205 
moths confined with plants in insect¬ 
rearing cages 124 died within 10 days, 
80 lived from 11 to 18 days, and 1 died 
on the 23d day. It was found that 
the average life of a female was from 
9 to 10 days, while that of a male was 
only 4 to 5 days. Thirteen moths kept 
in confinement without a plant lived 
from 3 to 9 days, with an average life of 
about 6 days. 
Activity 
The adults are nocturnal in habit, 
being more active at night, especially 
at dusk, when they may be observed 
flying in a zigzag fashion from plant to 
plant or swarming near the glass 
under the eaves. During the daytime 
they show much less activity and 
remain concealed, resting inconspicu¬ 
ously on the under side of the foliage 
or under the benches, or in other places 
where they are least likely to be dis¬ 
turbed; when alighting on a plant they 
immediately crawl to the under side of 
the leaves. Observations on the pro¬ 
portion of sexes in the third generation 
showed that there were about two 
females to every male, but in several 
later generations more males emerged. 
Egg Deposition 
Soon after mating egg deposition 
commences and may continue for 
about two weeks, the maximum num¬ 
ber being laid during the first few days 
and the number decreasing rapidly 
during the following week. In the 
case of a few individuals which lived 
three weeks or more, practically no 
eggs were laid during the last week. 
The female moth deposits her eggs 
singly or in clusters (PI. 2, B) on the 
under side of leaves during the night, 
egg laying rarely commencing until 
24 hours after emergence. 
The maximum number of eggs laid 
per individual was not definitely 
determined because the adults would 
usually die within two days whenever 
they were confined singly. In two 
instances only 42 and 80 eggs, re¬ 
spectively, were deposited within five 
days after emergence and the moths 
died three days later. It was neces¬ 
sary, therefore, to confine a number 
of individuals in a cage at one time. 
Under these conditions similar diffi¬ 
culty was experienced in securing 
satisfactory averages, as some of the 
moths would die after being in confine¬ 
ment for several days. The most 
reliable records were taken from the 
adults of the third generation and 
are given in Table II. 
Table II.— Egg-laying records for 
adults of the third generation of 
Phlyctaenia rubigalis 
Date of 
emergence 
Num¬ 
ber of 
moths 
emerged 
Date of 
oviposition 
Moths 
alive 
Num¬ 
ber of 
eggs 
depos¬ 
ited 
Apr. 25_ 
37 
Apr. 26_ 
37 
60 
26. 
<*29 
27.... 
66 
307 
28.... 
48 
42 
29_ 
43 
250 
30_ 
42 
174 
— 
May 1-2. _ 
41 
133 
3__ 
40 
344 
4_ _ 
40 
60 
6__ 
27 
0 
i 
7__ 
20 
0 
9__ 
1 
0 
— 
15.. 
0 
0 
Total.. 
1,370 
i 
a Sixteen moths removed for experimental use. 
In only one case was deposition 
observed during the day. Fresh plants 
placed in cages at 9 a. m. and examined 
in the evening were normally devoid 
of eggs, but if plants were left in all 
night many eggs were usually deposited 
on them. These records were cor¬ 
roborated by actual observations of 
20 moths confined with a calendula 
plant inside a lantern globe during the 
night of April 27, 1921. Eggs were 
deposited on both surfaces of the leaf 
and on the lantern globe at the follow¬ 
ing hours: 9.30, 9.50, 10.15, 10.30 p. m., 
and 12.15 and 1.25 a. m. By 4.25 a. 
m. the moths had become inactive and 
no more eggs were deposited that day. 
When ready to lay eggs the female 
bends the tip of her abdomen toward 
the leaf surface, after which the tube 
of the ovipositor is extended. The 
eggs are then forced out as small 
translucent droplets which the moth, 
with the aid of the third pair of legs, 
flattens out by pressing them so that 
they assume a scale-like appearance. 
During this operation the ovipositor 
is moved with a quick, nervous action 
from left to right, whereby the eggs 
are placed in successive rows forming 
regular clusters or patches (PI. 2, B) 
which may contain as many as 19, 
arranged in double or triple rows. 
Observations based on a total of 1,933 
eggs from 4 successive generations 
indicate that the number per cluster 
is normally less than 10. 
