PAEASITES 431 



The Muscidce are a very large family, several of which 

 are not only blood-suckers but transmitters of disease. 

 Musca domestica, the common house-fly, lays its eggs in 

 horse manure and here the maggots feed. Horses may be 

 largely prevented from attacks by the use of netting or a 

 body cover, also by keeping the stable dark, and hanging 

 up bushes or strings for the flies to settle on; further the 

 insects may be driven out by smoke. All these measures 

 are only partly successful by themselves, and more valuable 

 when combined. Well bred horses 

 are severely punished by the irrita- 

 tion caused by these flies. 



Stomoxys cakitrans (Fig. 183) re- 

 sembles the house-fly, and is often 

 mistaken for it, but the proboscis 

 projecting in front of the head dis- 

 tinguishes it. By means of this 

 proboscis it is capable of blood- Fig. iss.—stomoxj^s caid- 

 sucking and inflicting a severe <™»^ / twice natural size. 

 sting ; it is a most irritating fly in the stable. Within this 

 fly is passed the larval stage of a parasite of the ox, Filaria 

 labiato-papillosa, which is inoculated into the animal by the 

 bite of this insect. 



Closely allied to the above are the Hcematohia, blood- 

 sucking flies which never enter buildings but attack animals 

 at pasture. An American species, known as the 'horn-fly,' 

 selects the base of the horns to rest on, and attacks the 

 back, flank, and upper parts of the limbs. 



This fly not only irritates horses by its bite, but is a 

 carrier of disease ; it is believed to convey the trypano- 

 some of ' mal de caderas ' of the Argentine, and Haslam 

 found in the body of a Central African variety the trypano- 

 some of Tse-tse disease. 



The Glossina contains eight species, of which G. morsitans 

 genus is one of the most important.* This fly is found in 



* For a full accoimt of the Tse-tse flies, see the monograph on this 

 subject by Mr. Austen, British Museum of Natural History Pubhca 

 tions. 



Digitized by Microsoft® 



