144 



PARASITES OF THE DOMESTIC ANIMALS 



D. reticulatus so closely that a hand lens is necessary to distinguish be- 

 tween them. The body is oblong oval in shape and may measure as 

 much as three-fifths of an inch in length. It can be distinguished from 

 the Texas-fever tick by the capitulum and scutum which are longer and 

 broader. Extending anteriorly along each side of the scutum there are 

 lines of yellowish white rust, separated by a central brownish area. 

 There are eleven festoons on the posterior margin of the body, most 

 distinct in the young female. 



This tick has been foxmd on man, cattle, dogs, horses, and other an- 

 imals, especially in the Eastern United States. 



Fig. 82. — Dermacentor variabilis: male — enlarged (after Os- 

 born, Bull. No. 5, Bureau of Entomology, U. S. Dept. of Agr.). 



5. Margaropus annulatus (Boophilus annulatus, B. bovis). The 



Texas-fever or Cattle Tick. Margaropus (p. 142). — This tick may be 

 distinguished from the other five by the small size and the color of the 

 capitulimi and scutum, the lateral borders of which are straighter and 

 more parallel. These parts are short and relatively broad and in color 

 reddish brown or chestnut brown. The body is oblong oval in shape 

 and may reach a length of one-half an inch. The color may be dull 

 yellow or olive brown. Often it is mottled with irregular areas of 

 yellow and brown or streaked with wavy lines of these colors. Festoons 

 are absent. The legs are brown, moderately long, and very slender. 



This tick is found principally on cattle, less frequently on horses, 

 mules, and asses. 



