THE SATTX MOTH, A RECENTLY INTRODUCED PEST 7 
The moths emerge during a period of three to four weeks, begin- 
ning in the latter part of June, and are most abundant in the month 
of July. Those of both sexes are strong flyers and are attracted to 
lights, especially in the darkness of the early evening. European 
records indicate that great numbers of moths fly long distances, but 
such migrations have not been observed in this country. The moths 
move about during the day and fly short distances when disturbed, 
but are more active at night and are often abundant around street 
lights. In laboratory experiments the females have lived from 6 to 
20 days, and the average length of life was 10 days. 
MATING AND OYIPOSITION 
Mating usually takes place within a few hours after emergence. 
While the moths are in coitu their heads are in opposite directions, 
and they may remain, in that position for several hours. In a heavy 
infestation mated pairs may be found in this position on trees, grass, 
or bushes, and in some cases on electric-light poles, or on buildings 
near by. Both sexes frequently mate more than once, especially if the 
female has been disturbed during oviposition. The eggs are some- 
times deposited near the place where the female emerged, but in 
many cases a long flight may be made before the eggs are laid. 
Egg laying takes place during July, being at its height ajbout the 
middle of the month. The clusters of eggs are deposited principally 
on the trunks, the under sides of the branches, and the leaves of 
trees ; but they are also frequently found on fences, stones, buildings, 
or electric-light poles that are located near trees or brilliant lights. 
Glendenning 5 reports that — 
Twenty-five egg masses were counted on July 28, 1921. on the faces of the 
clock on the tower of the Burns Building, Vancouver. British Columbia. This 
building is nearly 250 feet high, and the clock is illuminated at night, which 
probably accounts for the eggs being there. This apparent carelessness is. 
however, no doubt occasionally the means of dispersal to fresh locations, when 
the eggs are laid on movable objects. 
THE EGG 
The eggs are laid in patches which are somewhat oval in form, 
averaging in size 15 mm. long and 12 mm. wide. Each patch is 
easily seen, being covered with a satin-white secretion which glistens 
in the sun. (PI. 1, 5.) 
Eggs spherical, but slightly flattened : light green when freshly laid, grad- 
ually becoming brown as embryo develops. 
The number of eggs in egg masses deposited in the field averaged 
316, as determined by an examination of large numbers of clusters. 
The largest mass collected in the field contained 412 eggs. There is 
a great variation in the size of these clusters, owing to the habit of 
the female of moving about if disturbed and so depositing more than 
one mass. 
In an experiment involving 46 fertilized females, two deposited 
over 1.000 eggs each. The greatest number deposited by one female 
was 1.023, and the average number for the experiment was 571. This 
number is greater than the average for field records. 
5 Page 10 of publication cited in footnote 3. 
