THE ACARIXA OE MITES. 



131 



few days apart, in order to kill any mites that may have hatched since the first applica- 

 tion. All underclothes and bedding should be ^Yashed in boiling-hot water. The 

 Xorwegian itch mite is S. scabei-crustosae Furstb. It produces a coarse, leprous crust 

 infested on the inner surface with myriads of the mites. 

 It is much less common than the other species. 



Nearly all of the domestic animals may harbor a 

 species of Sarcoptes peculiar to them. The more com- 

 mon are those of the hog, horse, and sheep. They 

 work like the human species, and are amenable to the 

 same treatment, or that used for sheep scab. 



The species of the genus Psoroptes have piercing 

 mandibles, and do not burrow. One species, P. com- 

 munis var. ovis Hering (figs. 268, 269), is the cause of 

 sheep scab , a serious disease of this animal throughout 

 the world. The fleece of scabby sheep presents a rough 

 appearance, the wool in places being stuck together in 

 greasy masses. The mites are most abundant around 

 the edges of an infested patch and increase very rapidly. 

 The eggs hatch in 2 or 3 days, and in 15 days they 

 become mature. The female lives for several weeks 

 and deposits a great number of eggs, commonly in 

 patches of about 20 each. By rubbing against posts, 

 trees, and fences patches of wool, containing mites and 

 eggs, are removed which may infest healthy sheep rub- 

 bing against the same places from other causes. The 

 loss is usually heaviest in autumn and early winter. 

 Sheep if not treated may soon become so enfeebled 

 through fatigue and lack of rest as to die. The best 

 remedy is to dip the sheep in some poisonous solution. 

 Various dips are in use, mostly based on tobacco, sulphur, tar, or lime. The famous 

 Rutherford dip, which has been very successful, is prepared by using 1 pound of 

 tobacco, 1 pound of sulphur, and 4 gallons of water. The tobacco is steeped for some 



time in water, the sulphur is added to this tobacco 

 water, and then the mixture is diluted by the requi- 

 site amount of water. It is best used warm. It is 

 customary to give another dip about 6 or 8 days 

 after the first, so as to catch the mites that have 

 hatched since the first dip was applied. Gillette 

 has used an 8 per cent kerosene emulsion, and con- 

 siders it cheaper than anything else. It is said that 

 in Europe shepherds apply a salve containing mer- 

 cury and oil of turpentine. If the sheep have been 

 kept in stables, these should be cleaned, the surface 

 soil removed, and the woodwork whitewashed to a 

 height of 4 feet. 



The species of Chorioptes (fig. 270) do not burrow 

 in the skin, but produce a scab similar to sheep scab ; 

 but it is restricted to certain parts of the animal, as 

 the feet, the ears, or the neck. Species occur on 

 the horse, ox, sheep, and goat. C. equi Gerlach attacks the hocks of horses, causing 

 the hair to fall out, and later sores, which cause the animal much annoyance. A mix- 

 ture of 1 part carbolic acid to 15 or 20 parts of oil will destroy the mite. In Australia, 

 Froggatt has noted that the mites attack patches of white hair by preference. The 

 genus Notoedres (fig. 271), differing from Sarcoptes in the dorsal anus, occurs on cats and 



Fig. 270.— Chorioptes setiferus. 

 (Origmal.) 



Fig. TaI.— Notoedres muris. 

 (Original.) 



