18 



BULLETIN 1218, U. S. DEPARTMENT OF AGRICULTURE. 



side of the median line, each bearing a bristle; considerably posterior to these 

 are 3 smaller nonchitinous tubercles, the anterior one on the median line, 

 the two others at each side and slightly posterior. Postero-laterad to these 

 upon each side is a tubercle bearing a bristle. On latero-ventral aspect of 

 prothoracic region posterior to wedge-shaped teeth 2 tubercles occur upon each 

 side, each bearing a bristle. 



Thoracic spiracle with rinia broadly curved. In the female no book occurs. 

 but in the male a distinct book occurs at the anterior end. 



Each abdominal segment except the rirst and eighth bears a complete double 

 circlet of bristles, the posterior circle being the longest. On the eighth, or 

 anal segment, there is a dorso-lateral fringe of bristles, and in the male a con- 

 tinuous fringe of bristles on the ventral aspect, but in the female the ventral 

 fringe is interrupted on tlie median line. Terminal teeth of anal segment 

 about equal in size. 



The descriptions of pupa and larva were made with the aid of a 

 binocular microscope. 



Life History. 



The egg of Tabanus punctifer averages 2.7 millimeters long and 0.3 milli- 

 meter thick (tig. 10. a). The basal part of the egg is more blunt than the 

 distal part, which tapers to a small dimension. The shell has no thickenings 

 or ridges. There is no operculum. When deposited the egg is snow-white. 



INCUBATION. 



Four accurate records were obtained of the incubation period of 

 T. punctifer. They are given in Table 1 . 



Table 1. — Incubation period of Tabanus punctifer. 





Egg mass. 



Temperature din- 

 ing incubation. 



Date. 



Egg 

 mass 

 No. 

 8715. 



Temperature dur- 

 ing incubation. 



Date. 



No. 

 7693. 



No. 

 7694, 

 Breed- 

 ing 

 No. 1. 



No. 

 7694, 



Breed- 

 ing 



No. 2. 



Max. 



Min. 



Mean. 



Max. 



Min. 



Mean. 



1918. 



C 1 ) 



(') 



(') 



°F. 

 84.0 



85.0 

 84.0 

 87.0 

 82.0 

 79.0 

 79.0 

 77.0 

 71.0 

 74.5 

 75.0 

 80.0 

 80.5 

 73.5 

 79.0 



°F. 

 43.0 

 43.5 

 42.0 

 37.0 

 44.5 

 40.0 

 42.0 

 33.0 

 35.0 

 38. 

 38.0 

 33.5 

 34.0 

 34.5 

 38. 



°F. 

 63.5 

 62.2 

 63.0 

 62.0 

 63.2 

 59. 5 

 60.5 

 55. 

 53.0 

 56. 2 

 56.5 



1919. 

 Aug. 13 

 14 

 15 

 16 

 17 

 18 

 19 

 20 

 21 



0) 

 " "(V)" ' 



°F. 

 92.0 

 93.0 

 95.0 

 96.0 

 93.0 

 94.0 

 96.0 

 98.0 

 98.0 



°F. i °F. 

 42.1 67.0 



10 



44.2 

 45.3 

 55.7 

 49.0 

 49.0 

 44.2 

 48.3 

 48.8 



68.6 



11 









70.1 



12 









75.8 



13 









71.0 



14 









71.5 



15.. . 









70.1 



16 





73.1 



17 





73.4 



is 









19.. . 

















20 





( 2 ) 





56.7 

 57.2 

 54.0 













21 . : 















22 



















■v, 



( 2 ) 





( 2 ) 























Incubation period (in days). 



14 



11 



14 











8 























Average daily mean tern- 



°F. 

 58.4 



F. 

 58. 9 



°F. 



58.4 













°F. 













71.7 





















Deposited. 



s Hatched. 



figured 



The mean temperature on the day of oviposition was not 

 in the average mean. 



No. TOOd was placed in direct sunlight on August 16 and kept 

 there each day until hatching. Xo record was kept of the actual 



