SABCOPTES SCABIEI COMMUNIS. 399 



and sucks the blood, and is generally seen in setters or pointers, 

 and dogs when working through the woods and underbrush be- 

 come filled with them. Turpentine and petroleum will destroy 

 them instantly. 



Leptus Autumnalis. 



This is what is known as a " harvest bug," or acari. It is about 

 4 mm. in length,, and is the red larva of thrombidium holoseri- 

 oeum. While human beings are quite frequently affected with 

 this parasite, it is only rarely found in the dog. Defrance and 

 Friedberger have seen pustular inflammations of the skin of the 

 dog produced by this parasite. The rash was very prominent on the 

 abdomen and the inner fascia of the legs, and was healed quickly 

 by an application of carbolic acid and glycerin, or carbolated 

 cosmoline. 



Dermatophagus Ganis. This is very rarely found in the dog, 

 and is a parasite which affects the ear, producing otitis externa. 

 For further details refer to Parasitic Otitis (page 381). 



The following parasites belong to the second group : 



Sarcoptes Scabiei Communis. 

 (Sar Coptic Mange; Scabies Sarcopiica.) 



Description of the Sarcoptes. This para- fig. no. 



site is about 0.25 to 0.30 mm. broad and 

 from 0.20 to 0.50 mm. long. It has a 

 rounded, turtle-like shape and a horseshoe- 

 shaped bead, with well-developed club- 

 shaped scissor-like jaws. It has short 

 rudimentary feet, and tulip-shaped suction 

 cups which are attached to the first, second, 

 and fourth pairs of feet in the male, while 

 in the female they are found in the first jen^aie sarcoptes of the dog, 

 and second pairs only. In the back we magnified 75 times, giving the 



. , , , abdominal view. (Siedam- 



see a number ot acorn-shaped scales or geotzky.) 

 thorns, and four rows of lance-shaped 



scales on the upper surface of the back. The skin shows trans- 

 verse folds and we find four elongated hairs on the posterior end 

 of the body. (Fig. 90.) 



