88 THE EEPORT OF THE No. 36 



houses are the Clover Mite (Bryohia prate^isis) and the Cheese Mite ( Tijroglyphus 

 longior). The Clover Mites often swarm in houses in the fall of the year, where 

 they frequently hibernate through the winter. They get into the cracks and 

 crevices of chairs, windows, doors, etc., and cause great annoyance to the occu- 

 pants of the house. The Cheese Mite is even a more serious pest, intruding itself 

 into all the darker parts of the house. It is found in the cellar, on fruits, 

 tubers and other food products; in the pantry on cheese, butter, flour, meat, 

 pastry, etc.; in the wardrobe, particularly on worn and stained clothing; in the 

 library on the paste of the book bindings ; in upholstered furniture in all the niches 

 and hollows where they can conceal themselves. Still more annoying is their 

 habit of crawling from the clothing to the body, and in many cases, while not 

 actually on the person, the imaginary discomfort is just as effective. The species 

 is not parasitic. Fumigation with hydrocyanic acid has given fairly satisfactory 

 results as a remedy for this mite. 



Domestic Animals. Most of the injurious parasites of domestic animals, 

 such as sheep scab, mange, ticks, follicle mites, belong to the Acarina. The sheep scab 

 caused by the mite known as Psoroptes communis, var. ovis, is a serious disease of 

 the sheep throughout the world. In Ontario it has occurred in Manitoulin Island 

 and a few other parts, but by proper precautions it has either been exterminated 

 or kept in check. They live in the skin, and obtain blood or lymph as food from 

 the host, and in this manner give rise to considerable irritation, resulting in inflam- 

 mation, scab formation, and finally in loss of wool and hair. The best treatment 

 consists in using some external applications, such as dipping, which will kill the 

 parasites. 



The disease known as mange is caused by species belonging to two different 

 genera, Sarcoptes and Chorioptes. The Sarcoptes when ,young burrow in the 

 tissue, where they feed and develop. The species of Chorioptes 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 and the neck. A species of Sarcoptes 

 causes eruptions and inflammation of the skin of horses, which becomes intensely 

 itchy, the animal at this stage refusing food and becoming much emaciated. A 

 species of Chorioptes is found on the horse, cattle and goat, the one attacking the 

 horse being the most common. 



Scarcely any of the domestic animals escape the attacks of the mites known 

 as ticks. The ticks are large mites with tough, leathery skin, and possessing 

 mouth parts fitted for sucking and legs fitted for holding on to the host. They 

 are true external parasites and cause much annoyance by getting into the ears, 

 around the eyes, and other places where they can avoid the efforts of the animals 

 to dislodge them. They are most abundant in the tropics, but a few species are 

 native to Ontario, and others again, such as the Southern cattle tick (Boophilus 

 bovis), are imported to this country along with the stock. 



The follicle mite of swine (Demodex phyloides) is the chief member of the 

 mite class attacking swine. They live m the follicle and cause white tubercles on 

 the skin from the size of a pin-head to that of a pea. 



Wild Animals. — These, of course, are not of so great economic importance, 

 but when further studied they may be found to play a part in the transmission of 

 disease from wild to domestic animals or man. It is astonishing to find on some 

 animals such vast numbers of these pests. The ground hog is especially a victim to 

 a number of species. The muskrat, the squirrel, the bat, the mole, the mouse, the 



