134 



DIPTERA OF MINNESOTA. 



or so below the surface, turn into pupae, and after about four weeks 

 in this stage, emerge as perfect flies. Until 1890 it was supposed 

 that the eggs were laid on the back, and that the maggots penetrated 

 the skin directly at that place. 



Fig. 127. The Striped Warble-fly or Heel Fly. Enlarged. Lugger. 



Hypoderma bovis, De Geer, is the most commonly described ox 

 warble fly, but it is doubtful whether this species is found in the United 

 States, and probably the injury to stock in this direction should be 

 ascribed to the Striped Warble Fly, or Heel Fly, Hypoderma lineata, 

 Villers, shown in Fig. 127. This is a hairy fly, looking a little like 

 a dark colored bee. There are yellowish white hairs on the thorax, 

 while above the abdomen is banded with black and whitish. Four lines 

 on the thorax give its name, the Striped Warble Fly. The name "Heel 

 Fly" comes from the fact, according to the statement of cattle men in 

 the Southwest, that it lays many eggs on the heels of the cattle above 

 the hoofs. The eggs are attached to the hairs by a peculiar clasping 

 apparatus at one end. 



It wQvfld appear from a report appearing in the Farmers' Review 

 for 1889 that at that date this parasite was practically unknown in 

 Minnesota and Dakota. But that we have it now to some extent is an 

 undisputed fact, and doubtless it will increase in time, as more stock 



