26 BULLETIN 597, U. S. DEPARTMENT OF AGRICULTURE. 



254 males and 181 females were used in the experiments. All of 

 these emerged normally from reared material. While some adults 

 died on the first and second clays 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 light 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. These 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 clays. Some adults captured in nature were kept under simi- 

 lar conditions and lived from 3 to 5 clays. 



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 



