208 
JOURNAL OF ECONOMIC ENTOMOLOGY 
[Vol. 11 
the dark mailing tube. The ratio of the total number of adults which 
had emerged before exposure to light as compared with the total num¬ 
ber which emerged after exposure to light, either from egg clusters 
from which no adults had previously emerged or from which some 
adults had already emerged, expresses what has been assumed to be 
the emergence response to light. A few examples of individual daily 
observations are given. 
In the following table, all the observations, summarized, are given. 
Ratios of Emergence Response of Trichogramma to Light 
Days after 
Collection 
7 a. m. 
9 a. m. 
10 a. m. 
11 a. m. 
12 m. 
1 p. m. 
2 p. m. 
3 p. m. 
4 p. m. 
6 p. m. 
Average 
1 
25.33 
/ .66 
\ 2.12 
2.69 
1.08 
1.27 
/ 2 
\ 2.78 
2.17 
.47 
.2 
3.7 
(1.51 
2 
2.28 
3.36 
.67 
. • • • 
\ .65 
.73 
.71 
1.22 
1.34 
1 .93 
3 
5.11 
4.23 
1.71 
.25 
1.26 
> • • 
.42 
.12 
1.87 
4 
.95 
.36 
.4 
.25 
.81 
.55 
5 
i .55 
.21 
. 
.88 
6 
.... 
.... 
.35 
.5 
.42 
Average 
15.22 
2.17 
2.59 
.9 
.63 
1.36 
.74 
.76 
.7 
.27 
.... 
The number of hours between the observations on succeeding days 
bore no constant relation to the emergence response, and is not indi¬ 
cated. It is obvious that the emergence response is not as strong sev¬ 
eral days after collection. This ma}^ be due to unnatural conditions 
of moisture, curling of the bit of cane leaf, or fungus growing on it, 
but it may also be a result of the lessened chance of an organism re¬ 
sponding to light when it has experienced only one twelfth (±) as 
much as it normally would receive. There was no way to differentiate 
between the egg clusters from which Trichogramma would emerge in a 
few hours and those in which several days were necessary for develop¬ 
ment, and both consequently received the same treatment. Thus the 
adults emerging in four or five days received ordinary room light for 
only four or five hours plus the light before collection, while those 
emerging the next day after collection had been exposed to bright 
sunlight twelve or more hours a day, except for a short period just 
prior to emergence. 
It is also to be noted that the emergence response of Trichogramma 
is not as strong in the late morning, or afternoon, as earlier in the 
day. This is to be expected. In the field, Trichogramma adults just 
emerged from the eggs have been observed at the following times: 
7.15 a. m. (July 24), 8.15 a. m. (July 27), 8.05 a. m. (August 1), 7.45 
a. m. and 8.10 a. m. (August 7), 7.15 a. m. (August 9), 8.45 a. m. 
(August 13), 8.15 a. m. (August 14). The average of these times is 
8.06 a. m. Adults have not been seen at other times, although obser- 
