12 



CIRCULAR 338, U. S. DEPT. OF AGRICULTURE 



Figure 8.— The American dog tick or wood tick, 

 Dermacentor variabilis. Left, engorged female; right, 

 male. Dorsal views. Enlarged. From Banks, 1908. 



The American dog tick (fig. 8) usually occurs as an adult tick on 



dogs, the earlier stages (those of seed tick and nymph) occurring on 



various small mammals. It attaches to various" parts of the body, 



but displays a preference for 

 the ears. When fully en- 

 gorged with blood the female 

 tick is almost half an inch 

 long and of a bluish color, 

 with a reddish-brown shield 

 with white markings on the 

 back near the head. This 

 species occurs in the eastern 

 half of the United States, in 

 parts of the west coast, and 

 occasionally elsewhere in this 

 country. 

 The brown dog tick (fig. 9) occurs on dogs as seed tick, nymph, 



and adult. It frequently attaches inside a dog's ears, sometimes deep 



in the ear canal. The young ticks 



are likely to be abundant in the 



long hair on the neck, but any stage 



may occur on almost any part ot 



the body, including the spaces be- 

 tween the toes. In this country 



this tick occurs in the South, being 



reported from Texas, Louisiana, 



Mississippi, and Florida, but it 



may be found farther north, being- 

 reported from Ohio, Pennsylvania, 



and New York. Its occurrence 



in these Northern States is due, no 



doubt, to the fact that dog owners 



have transported ticky dogs, mostly 



bunting dogs, from the South to 



the Northern States. It appears 



to have taken up the habit of 



living indoors over winter as an 



adaptation to cold winters, and 



according to F. C. Bishopp, of the 



Bureau of Entomology, and reports 



from various persons, causes seri- 

 trouble by establishing itself 



ous 



in kennels and about houses. 

 Symptoms. — Ticks 



cause 



local 



Figure 9.— The brown dog tick. Rhipiccphalus 

 sanguineus: a, Male; a, onengorged female. 

 Enlarged* From Mcintosh, 1931. 



irritation at points of attachment, 

 and dogs commonly bite or scratch 

 these places. In heavy infesta- 

 tions the injury may be serious. In addition to the local injury 

 there is a loss of nervous energy from irritation. The tick buries 



