36 PARASITES OF THE DOMESTIC ANIIVIALS 



after-effect from the bites of these flies they are a source of much tor- 

 ment to Hve stock, not only in the pain produced by their punctures, 

 but in their pecuhar buzzing, which often terrorizes nervous animals, 



their frantic and heed- 

 less efforts to escape not 

 infrequentlj^ resulting 

 in injury. 



There can be no 

 doubt that the Taba- 

 nidae are concerned in 

 the transmission of cer- 

 tain blood diseases of 

 live stock. It is signif- 

 icant as to their possi- 

 bihties as carriers of 

 anthrax that their at- 

 tack seems to be more 

 commonl}'- d ir e c t e d 

 against cattle than 

 horses. 



Protection. — Little 

 can be done toward 

 repelling the attacks of the flies. Horses at work are protected in a 

 measure by covering them with nets. Where the flies are numerous and 

 especially tormenting it is advisable to remove pasturing animals to a 

 well-shaded retreat during the warmer and sunnier parts of the day. 



Fig. 20. — Tabanus atratus: a, larva; b, pupa; c, adult 

 (after Osborn, from Riley, Bui. No. 5, Bureau of Ento- 

 mology, Dept. of Agr.). 



Tabanus Lineola 



Tabanidffi (p. 35).— The Green-head Horsefly (Fig. 21). This is the 

 most widely distributed species in North America. It is about five- 

 eighths of an inch in length. E^^es large and bril- 

 liant green, abdomen brown, with a conspicuous 

 grayish line running longitudinally on its dorsal 

 side. It is from this marking that its specific 

 name is derived, while the peculiar coloring of the 

 eyes gives to it the common name "Green-head." 



The oval, larval, and pupal stages are passed uneok (after Osbom; 

 in moist places, and in other respects the life cycle from Packard, Bui. No. 5, 

 is similar to that of Tabanus atratus, though the 

 larval period is probably not so long. 



The Green-heads appear in especially large numbers in marsh}^ dis- 

 tricts during the brightest and hottest days of the summer. They 

 attack in greater numbers than the Black Horseflies, and, especially 



Fig. 21. — Tabanus 



Bureau of Entomology, 

 Dept. of Agr.). 



