96 PARASITES OF THE DOMESTIC ANIMALS 



Famil}^ I. Gamasidae. — Poultry mites. 



Family II. Trombidiidae. — Harvest mites or chiggers. 



Family III. Sarcoptidse. — Mange and scab mites. 



Family IV. Demodecidae. — Follicle mites. 



Family V. Cytoleichidse. — Deep seated mites of birds. 



Superfamily Ixodoidea. — The ticks. 



Family I. Argasidce. — The fowl tick and ear tick. 



Family II. Ixodidge. — The cattle tick and other ticks. 



Each of these contains species parasitic upon mammals or birds with 

 the exception of the Demodecidae, which, so far as known, have only 

 been found upon mammals. 



The condition produced upon the host by the presence of parasitic 

 Acarina is designated medically as acariasis. Differing in their grade 

 of parasitism, the numerous species bring about a varying degree of 

 disturbance to the skin which they inhabit. Accordingly there is dis- 

 tinguished sarcoptic and psoroptic acariasis, the former produced by 

 species which burrow and form subepidermic galleries in which they 

 deposit their eggs, the latter by species living upon the skin's surface. 

 The term mange is limited by most writers to acarises caused by species 

 of the genus Sarcoptes and its near alKes, or by Demodex, both living 

 beneath the skin's surface, the last named in the hair follicles and se- 

 baceous glands. The psoroptic form, in which there is deep scab for- 

 mation, constitutes true scabies or scab, although these latter terms are 

 frequently used in a general sense relative to the condition produced 

 by the mange and scab mites. Acari belonging with the families Ga- 

 masidae, Trombidiidae, and the superfamily Ixodoidea do not cause 

 mange or scab. 



Classification of Parasites of the Class Arachnida 



Class B. Arachnida. P. 94. 

 Order I. Acarina. P. 94. 

 Family (a) Gamasidae. P. 98. 

 Genus and Species: 



Dermanyssus gallinae. Host, poultry. P. 98. 

 Family (b) Trombidiidae. P. 99. 

 Genus and Species: 



Trombidium holosericeum. Larvae attack man and lower 

 animals. P. 100. 

 Family (c) Sarcoptidae. Mange and scab mites. P. lOL 

 Genus and species: 



Sarcoptes scabiei var. Equi. Host, equines. P. 104. 

 S. scabiei var. 'Ovis. Host, sheep. P. 112. 

 S. scabiei var. Bovis. Host, cattle. P. 114. 

 S. scabiei var. Suis. Host, hog. P. 114. 



