16 
BULLETIN 1032, U. S. DEPARTMENT OF AGRICULTURE. 
The duration of the pupa stage varies from 10 to about 65 days, 
depending upon the weather and the time of the season. 
THE ADULT. 
The adults, or moths, of the blackhead fireworm are conspicuous 
because of their habits of flight; when disturbed they often rise in 
very large numbers. Upon close examination they are found to be 
small in size, measuring in length from the tip of the head to the 
tip of the wing on the average about 6 or 7 mm., a little over one- 
fourth of an inch, or about the same length as the mature larvae. 
With the wings spread they measure about 10 mm. across, or a little 
over three-eighths of an inch. 
The moths (fig. 9) differ somewhat in color, seeming to vary espe- 
cially according to age. The first pair of wings of freshly emerged 
'Fig. 8. 
-The blackhead fireworm : View of pupa and interior of cocoon. Enlarged about 
7.5 times. 
and unrubbed specimens have a ground color above of deep silver 
gray, with irregular markings of brown, which often give them a 
golden-brown sheen. Characteristic markings of a single row of 
short alternating brown and silver-gray bars running diagonally to 
the front margin are found on the first or upper pair of wings. The 
second or lower pair of wings of the female are without characteristic 
markings ; those of the male have an irregular dark spot on the under- 
side near the front margin. The second or lower pair of wings of 
both male and female have a fringe of long, bristlelike scales extend- 
ing from near the tip along the back margin to the body. The abdo- 
men is medium and slender, depending on the sex, female specimens 
having a somewhat broader and shorter abdomen than the males. The 
abdomen and the legs are covered with dark silver-gray scales, which 
