HORSE-FLIES AND WESTERN AGRICULTURE. 11 



lowing. August 25, 1916, 25 flies of this species were seen at one 

 time attacking a pony. 



The earliest appearances recorded for T. punctifer were May 

 28, 1919, at Lovelock, Nev., and at Topaz, Calif. On June 7, 1919, 

 several were captured in Slinkard Valley, adjacent to and several 

 hundred feet higher than Antelope Valley. The flies are most 

 abundant during July and the first three weeks in August. During 

 the last week in August they begin to decline in numbers and the 

 latest one recorded was seen September 21, 1916. 



Feeding Habits. 



The females (PI. I, B) of Tabanus punctifer attack horses and 

 cattle eagerly, usually biting the animal along the back and, when 

 numerous, on the jaws and neck. During the investigation there 

 was only one instance of this fly biting man. On August 20, 1919, 

 while the junior author was collecting at Alkali Lake, one bit him 

 on the back through a heavy khaki shirt. The bite was exceedingly 

 painful, being comparable to the thrust of a needle. The fly was 

 captured in the hand. Horses make a most determined resistance 

 to them. Cattle resist them less energetically; a cow lying down 

 was observed to remain passive while a fly fed to repletion. 



On July 29, 1919, T. punctifer was observed trying to feed upon 

 carcasses. During the forenoon several attempted to feed upon the 

 carcass of a cow dead for three days. Apparently they were unable 

 to puncture the skin, because after several attempts they flew away. 

 During the afternoon the carcass of a cow that had died only about 

 an hour before was found. During the period of about one-half 

 hour 14 T. punctifer were observed actually feeding on the carcass. 

 This animal was suspected of having died of anthrax. On August 18 

 the carcass of a horse dead for several days was found in a ditch. 

 The carcass lay half in water. Three T. punctifer attempted to feed, 

 but the one captured and examined contained no blood. On one 

 occasion a female attempted to feed upon a sack of forge coal. 

 After inserting her mouth parts through the meshes of the burlap 

 two or three times she flew away. 



On account of the excitement and interruption usually attending 

 a feeding of this fly in nature it was very diffcult to ascertain the 

 actual length of time required for the ingestion of a full meal of 

 blood. One accurate record is of special interest. On September 21, 

 1916, one was observed to alight upon a cow which was lying down. 

 The cow was perfectly calm and the fly fed to apparent satiety in 

 11 minutes and 10 seconds. 



Captured females refused to bite in captivity, as did also reared 

 females, save in one case. Female No. 128 emerged August 21, 1919. 

 On August 22 she was placed on a horse, a glass breeding jar being 

 held inverted over her. She did not try to feed. On August 26 she 

 was again placed on a horse. After brushing her labellum for half 

 a minute with her forelegs she began trying to feed. She punctured 

 the skin in four places, not feeding until the fourth puncture, where 

 she fed for a period of 10 minutes, apparently continuously. While 

 feeding her hind legs were extended in the air nearly parallel with 

 the body; the first and second pairs of legs supported her on the 



