84 THE HOUSE FLY AND ITS ALLIES. 



We now come to the more degraded forms of flies which 

 live parasitically on various animals. We figure, from a speci- 

 men in the Museum of the Peabody Academy of Science, the 

 Bird tick (Ornithomyia, Fig. 92), which lives upon the Great 

 Homed Owl. Its' body is much flattened, adapted for its life 



under the feath- 

 ers, where it 

 gorges itself with 

 the blood of its 

 host. 



Here belongs 

 also the Horse 

 tick (Hippobosca 

 equina, Fig. 93). 

 It is about the 

 size of the house 

 fly, being black, 

 with yellow spots 

 on the thorax. Verrill* says that "it attacks by preference 

 those parts where the hair is thinnest and the skin softest, 

 especially under the belly and between the hind legs. Its bite 

 causes severe pain, and will irritate the gentlest horses, often 

 rendering them 

 almost unman- 

 ageable, and 

 causing them to 

 kick dangerously. 

 When found, they 

 cling so tirmly as 

 to be removed 

 with some diffi- 

 culty, and they 

 are so tough as 

 not to be readily 



crushed. If one 



93. The Horse Tick, 

 escapes when cap- 

 tured, it will instantly return to the horse, or, perchance, to the 



*The External and Internal Parasites of Man and Domestic Animals. By Prof. 

 A. E. Verrill, 1870. We are indebted to the author for the use of this and the fig- 

 ures of the Bot fly of the horse, the turkey, duck and hog louse, the cattle tick, the 

 itch insect and mange insect of the horse. 



