120 PROC. ENT. SOC. WASH., VOL. 20, NO. 6, JUNE, 1918 



April 18. The flight was stronger than usual, of as long a dura- 

 tion as any during the season. The weather was warm 66F. at 

 the beginning of the flight. There were not as many adults of T. 

 americanus around the screens as usual. 



On April 19 the junior author again visited the senior author at 

 Paradise Key and made the following observations. A very 

 heavy cold rain lasted all morning. Beautiful bright green- 

 eyed males of the large T. americanus were found to be common 

 feeding on the blossoms of saw palmetto in the late afternoon. 

 We collected several dozen males and a few females before the 

 mosquitoes drove us indoors. Males of T. trijunctus with eyes 

 of a soft lavender color, and the purple-banded-eyed females 

 were also collected on this bloom, as were a few males of T. lineola. 

 The leaves of the palmetto shading the bloom were cut away by the 

 senior author to expose the bloom to sunlight and thus possibly 

 attract more flies. The senior author was able to detect a difference 

 in tone in the buzzing which the males and females make when 

 they are flying; the same comparison as between the worker and 

 drone honey bee. 



April 20 the writers made observations on a flight at 4.33 a.m. K 

 but it was very light, (Later, 5.25) with the sun rising above the 

 tree tops the first adults of T. trijunctus were observed flying. 

 At 6 a.m. no adults of T. americanus were as yet feeding on the 

 palmetto bloom. They remained in the hammock after the early 

 morning flight until the sun was well up. 



In the early morning the doors to the screened veranda were 

 opened and a count made of the gadfly adults which came in 

 between 6.40 a.m. and 7.20. Needless to say all were killed: 

 T. americanus 1 male; T. trijunctus 222 females, no males; T. 

 lineola 5 females. 



Between 2.30 and 3.30 p.m. several dozen T. americanus males 

 were caught feeding on saw palmetto blossoms, with ripe pollen; 

 also about a dozen males of T. trijunctus. At 5 p.m. the males of 

 T. americanus were not as common as early in the afternoon, and 

 but few were flying. Males of T. trijunctus were also collected. 



On April 21 at 4.20 a.m. the flight of T. americanus began. The 

 stars were visible and the red light of dawn was tinting the eastern 

 sky. The flight was strong, the loud buzzing lasted fifteen min- 

 utes but a few adults were flying at the end of seventeen minutes. 

 The flies hovered high among the tree tops at first, then when it 

 became lighter, lower. One male was caught hovering. The 

 senior author was able to see the legs of the flies sticking up in 1 1n- 

 air when they hovered reversed, with abdomen pointed upward. 



6 Central time. 



