10 PARASITOLOGY. 
The Arthropoda are those parasites that are pro- 
vided with jointed legs. This branch is divided into 
two classes, viz.: Insecta and Arachnida. 
Under the class Insecta are placed the orders: 
Diptera, Siphonaptera and Hemiptera. 
The order Diptera includes the following families, 
viz.: 
Culicidae, which include the gnats and mosquitoes. 
Simuliidae, which include the buffalo gnat. 
Tabanidae, which include the horse and ox flies. 
Muscidae, which include the horn-fly, the horse- 
fly, etc. 
Hippoboscidae, which include the sheep-tick. 
Oestridae, which include the bot-flies. 
The order Siphonaptera includes the fleas. 
Under the order Hemiptera are placed the follow- 
ing families, viz.: 
Pediculidae, which include the blood-sucking lice. 
Philopteridae, which include biting lice. 
Liotheidae, which include lice of birds. 
The first two families live upon mammals. 
The class Arachnida includes the orders Acarina’ 
and Linguatulida. 
The order Acarina includes the families Ixodidae, 
Argasidae, Gamasidae, Trombidiidae, Acaridae. 
The family Acaridae is divided into sub families, 
Sarcoptidae and Demodecidae. 
The families Ixodidae and Argasidae include the 
ticks. 
The family Gamasidae includes minute parasites 
of birds and small animals. 
The family Trombidiidae includes the chiggers. 
