26 BULLETIN 597, U. S. DEPARTMENT OF AGRICULTURE. 
254 males and 184 females were used in the experiments. All of 
these emerged normally from reared material. While some adults 
died on the first and second days the maximum longevity was 7 days. 
The greater periods were always obtained when the cages were kept 
out of the bright sunlight and provided with more or less foliage to 
prevent adults from battering themselves against the sides of the 
cage. Twenty-seven males and 15 females liberated in the insectary 
(9 by 12 by 7 feet) died within 1 to 3 days and were found dead 
at a sunny exposure with the wings battered. Cages admitting a 
great amount of hght and without foliage yielded similar periods of 
longevity. 
Adults in screen cages 18 by 18 by 18 inches or in a parasite- 
rearing box (covered on two sides with glass and arm holes in the 
ends) usually died within 3 days. This longevity was slightly ex- 
tended when green twigs were frequently replenished. 
The longest periods were obtained in wooden boxes 4 by 4 by 6 
inches half filled with moist soil and provided with a green twig 
and a glass cover. This lessened adult activity, and from the 51 
longevity experiments it was observed that the greater periods were 
always accompanied with the least activity, while the converse was 
also true. hese wooden boxes placed in the shade admitted enough 
light to permit of activity and flies were often observed to fly about — 
with the head near the glass and would alight on the green twigs 
and rest. The usual longevity under such conditions ranged from 
3 to 6 days. Some adults captured in nature were kept under simi- 
lar conditions and lived from 38 to 5 days. 
Various flowers were supplied as food for the adults, but in no 
case was feeding observed. Sweepings were also made from flowers 
blooming in pastures and from alfalfa in bloom, but adults were 
never captured under such conditions. 
ADULT HABITS. 
Adult flies in cages copulate most frequently about noon, the 
duration of the act ranging from 3 and 4 to 15 minutes. During the 
act the flies usually remain quiet, except for the distinct abdominal 
movements of the male. The male usually breaks from the female, 
leaving her at the place of copulation, but within a few minutes may 
be observed to return. One pair has been observed to copulate as 
many as four times within an hour. Males will mate with a freshly 
emerged female before her wings are dry, properly unfolded, or the 
body of a normal color. In nature the one object of the male seems 
to be copulation, and that of the female oviposition. Buzzing in 
midair about the horse the male may be easily caught with the hand. 
A female is only observed buzzing at a standstill in midair when 
