Sarcoptiformes 371 



dectes and Caparinae where they are on tarsi i and ii) . In the male legs 

 IV are considerably shorter than in. Tarsi in of the females end in long, 

 whiphke setae. The males have adanal copulatory suckers. The posterior 

 margin of the abdomen of the male is bibolate or slightly emarginate. 



Genera: 



1. Psoroptes Gervais, 1841 (= Dermatodectes Gerlach, 1857 = Der- 



matokoptes FLirstenburg, 1861) 

 Type. Sarcoptes equi Hering, 1838 



2. Caparinia Canestrini, 1894 



Type. Chorioptes setiferus Megnin, 1880 



3. Chorioptes Gervais, 1859 (= Symbiotes Gerlach, 1857 nom praeocc. 



= Dennatophagus FurstQnbuTg, 1861) 

 Type. Sarcoptes caprae Delafond, 1854 



4. Otodectes Canestrini, 1894 



Type. Sarcoptes cynotis Hering, 1838 



Discussion: The genus Psoroptes can be considered as consisting of 

 one species with the varieties existing upon the various hosts. These 

 varieties are only slightly differentiated morphologically (Hirst 1922) 

 and it is difficult or impossible to transfer the mites from one host to 

 another of a different species. 



Psoroptes equi var. ovis causes the disease known as sheep-scab 

 which damages the wool and at times causes the loss of the animals. 

 The psoroptic mange differs from the sarcoptic mange in being found 

 on the body wherever there is wool. The mites pierce the skin with 

 their chehcerae, causing the characteristic irritation, scabs, and exu- 

 dation of serum. The wool may become matted and even detached in 

 some cases. The mites live under the scabs formed by the exudation 

 of the serum at the site of the punctures and their activity continually 

 adds to the thickness of the scab. Van Es 1904 states that "weak ani- 

 mals or such as are not well cared for show the physical effects of the 

 disease in the form of loss of flesh, anaemia, and an increased weak- 

 ness which may be the forerunner of a fatal termination." They are 

 readily transmittable through direct contact or through infected ma- 

 terials. It is world-wide in distribution. 



Psoroptes equi var. caprae is to be found on goats but is confined 

 to the ears. Usually the mite is not a serious pest but at times can 

 cause deafness, loss of appetite, and, in extreme cases, death of the 

 animal. 



Psoroptes equi var. cuniculi is to be found in the ear of rabbits and 



