PARASITIC DISEASES OF THE SKIN. 259 



associated with scab. Their favored locations appear to be the 

 inner part of the thigh and sides of the neck. 



Their presence on the sheep produces considerable discom- 

 fort, a thickening of the skin, which becomes rough and covered 

 with dry blackened scales, the wool becoming dry, brittle, and 

 lifeless, giving the sheep an appearance of being out of condition 

 generally. Sheep harboring lice will rub against posts and nib- 

 ble at their flanks, frequently scratching the elbows with the 

 hind feet. When affected sheep lie in the sun, the parasites 

 strike for the outside of the fleece, a careful examination reveal- 

 ing multitudes of small brown parasites. 



Crcatrtietit. 



A thorough dipping or a dressing with a preparation of 

 sulphur will quickly rid the sheep of this form of parasite. 



"Cbc fly. (LuceUta JVIarccUaria.) 



This insect is the chief cause of maggot in sheep in the 

 United States. It, according to Neumann, "measures from one- 

 third of an inch to half an inch in length, and is recognized by 

 its blue thorax, streaked with the darker blue bands of a purple 

 tint; the pads are black, and the wings brown at the base. The 

 larva measure from one-half to five-eighths of an inch in length. 

 This fly is met with over a great portion of America, from the 

 North of the United States to the Argentine Kepublic." The 

 fly deposits its eggs on the wool, the larvae living on the yolk, 

 the most favored location being the base of the tail, especially 

 should the animal be suffering from diarrhoea or dysentery, 

 then all parts contaminated with the discharge are attacked by 

 the fly. Any sores, such as those caused from fighting in rams 

 or wounds and abrasions of any kind, are liable to attack during 

 the fly season. As soon as the eggs hatch the larvae or maggots, 

 as they are termed, begin to burrow into the tissues, causing 



