UNITED STATES DEPARTMENT OF AGRICULTURE 

 BULLETIN No. 597 



Contribution from the Bureau of Entomology 

 L. O. HOWARD, Chief 



Washington, D. C. 



PROFESSIONAL PAPER 



April 9, 1918 



SOME BIOLOGICAL AND CONTROL STUDIES 



OF GASTROPHILUS HAEMORRHOIDALIS AND 



OTHER BOTS OF HORSES 



By 



W. E. DOVE, Scientific Assistant 

 Insects Affecting Domestic Animals 



CONTENTS 



Page 



Introduction 1 



Brief Life History of Gastrophilus . . 2 



Historical 2 



Species Differentiation 3 



Distribution in the United States and 



Probable Dispersion 5 



Larval Collections and Rearing Tech- 

 nique 5 



Larval Infestation and Injuries .... 6 

 Bot-fly Annoyance 13 



Page 

 14 



Natural Protection of Horses . . 



Seasonal History of Gastrophilus ... 15 



Gastrophilus haemorrhoidalis Linn . 16 



Gastrophilus nasalis Linn 30 



Gastrophilus intestinalis DeGeer . . 32 

 Effect of Death of Host upon Gastro- 

 philus Larvee . 34 



Control Studies 35 



Summary 48 



Bibliography 50 



WASHINGTON 

 GOVERNMENT PRINTING OFFICE 



1918 



