SB 

 818 

 C578 

 ENT 



No. 25, Second Series. 



nited States Department of Agriculture, 



DIVISION OF ENTOMOLOGY. 



THE OX WARBLE. 



{Hypodenna lineaia Villers.) 

 GENERAL CHARACTERISTICS AXI) ORIGIN. 



One of the worst insect enemies of cattle, especially in the o:reat 

 grazing regions of the West and Southwest, is the so-called ox bot, 

 or ox warble. It bears, also, a number of other colloquial designa- 

 tions, such as the ''ox wormal," "bot-fly/' "heel fly," and is often 

 known merely as the "grub." With reference more particularly to 

 the injury occasioned b}' it, we haye the terms "grubby cattle," 

 "warbled stock," and the expressions "licked beef," or "jelly," in 

 description of the peculiar appearance of the region infested on the 

 beef and on the hides. 



This insect (fig. 1) belongs to the 

 family CEstridse, which includes the 

 gadflies and bot-flies, various species 

 of which affect all of the larger her- 

 biyorous mammals, some of them Hying 

 in the cavities of the body, as in the 

 nostrils and the digestive tract, and 

 others beneath the skin, as is the case 

 with the species under discussion. Un- 

 til comparatively recent years tlie gen- 

 eral belief has been that our ox bot-fly 

 was the common warble fly of the Old 

 World (Hypoderma hovis, fig. 2), but it 

 has been more recently shown that the 

 only bot-fly affecting cattle so far dis- 

 covered in this country is a different 

 species (Hypoderma lineata) . This spe- 

 cies is also quite abunchmt in Europe, where it occurs in company with 

 the old species //. hovis, and often on the same animal. The Hypoderma 

 lineata is a common cattle pest throughout the United States, and 

 infests also the buffalo. In Europe it has l)een found from England to 

 the regions of the Balkans and the Caucasus. AVhether it is of European 

 or American origin can not be very readily determined. It was present 

 32356— No. 25—06 



Fig. 1. — Hypoderma lineata— tv.mnle, nat- 

 ural size indicated by side line (from 



Insect Life). 



