134 
Journal of Agricultural Research 
Vol. XXI, No. 3 
THE MOTH 
DESCRIPTION 
The adult is a small, grayish moth with a wing expanse of 12 to 15 mm. 
The head, fore wings, and thorax are of a silvery gray color irregularly 
marked with black. The antennae are white annulated with black. 
The face is white. The hind wings are white dusted with fuscous; the 
cilia slightly ocherous. The abdomen is silvery white. The legs are 
white barred with black. The females are slightly larger than the males. 
(PI. 29, A.) 
EMERGENCE, LONGEVITY, AND HABITS OF FLIGHT 
• 
The moths emerge every alternate year, as in 1913, 1915, 1917, and 
I 9 I 9* First adults appear in the field between July 5 and 10, and emer¬ 
gence is continued until about August 15, reaching a maximum about 
July 25. The average length of life of the adults, as appears from data 
obtained on adults reared in field cages, is approximately 14 days. All 
observations indicate that the moths are most active during the warmer 
part of the day; myriads may be seen flying during the maximum period 
of flight and active on the foliage of the host on warm days between 10 
a. m. and 4 p. m. After 4 p. m. at these high altitudes the temperature 
drops considerably and the moths cease flying and are not so active on 
the foliage. On cloudy days the moths hide away among the foliage 
and in the crevices of the bark of the tree trunks and fly out only 
when disturbed. 
MATING AND EGG LAYING 
Copulation was observed in the field on one occasion only. Numerous 
observations were made in the field and on moths kept captive in a 
cage to determine the approximate period of mating, but this one in¬ 
stance is all that was recorded. This occurred about 11 a. m., July 25, 
1919. When first noted the pair was attached and quietly resting on a 
small lodgepole pine branch a few inches from its outer end. 
Opposition was observed once only and in the field at 1 p. m., July 27, 
1919. When first noted, the moth was in position to oviposit at the 
base of the 1919 needle growth on the tip of a small twig about 5 feet 
above the ground. It was facing the tips of the young needles and had 
the ovipositor inserted between and under the needle sheaths and against 
the branchlet. This appears to be the normal position, as practically 
all the eggs that were found in the field were located under the needle 
sheaths or on the surface of the twigs near the base of the 1919 needle 
growth. (PI. 29, B.) After this moth had been under observation for 
five minutes she was collected and it was found that she had deposited 
three eggs in this position. Later the moth was dissected and nine 
more eggs were secured. The foregoing record of oviposition was made 
