212 Veterinary Medicine. 



to the mite while the variety found on any special animal is fur- 

 ther named after its host. 



The Demodex Folliculorum has a broad short rostrum with 

 chelicerse, jaws and tongue ; a cephalo-thorax, one-third longer 

 than broad, and furnished with four rudimentary limbs, on each 

 side, on the flat ventral aspect, and close to the border ; and 

 lastly the conical worm-like abdomen, about three times the 

 length of the cephalo-thorax and finely striated across. They are 

 oviparous, the egg being elipsoid, and the young pass through the 

 same stages of hexapod larva ; octopod, non-sexual nympha ; 

 sexually mature male and female ; and ovigerous female that are 

 seen in other acarina. 



Demodex Folliculorum var. Hominis. This inhabits the 

 sebaceous glands of the human face, especially the nose, and 

 when twelve or more exist in one cavity they give rise to the 

 acne-like swelling known as Comedon. The female measures 

 .38 mm. and the male .30 mm. in length. 



Demodex Folliculorum var. Canis. The female measures 

 .25 to .30 mm. long ; the male .22 to .25 mm. 



It lives in the sebaceous glands, of the eyelids, toes, elbows 

 and hocks, and later by extension on any part of the body. At 

 first there are redness, depilation, small papules and a slight scur- 

 fincss of the affected spots. I^ater the redness becomes intense, 

 the skin thickened, scabby, corrugated and bald, with more pro- 

 jecting papules and pustules. The papules may show a dark- 

 bluish red color, or they may be pink with a whiteish center. 

 In some instances the follicle is open and discharges a pus- 

 like fluid in which numerous acari can be found. In some in- 

 stances pressure forces out a cylindroid mass of sebum which 

 being dissolved in alcohol or ether shows abundance of the acari. 

 As in other parasitic affections causing evulsion of the hair (ring- 

 worm) there is a tendency to form circular Ijald spots {circinate 

 form), on which, in this case, the papillary elevations appear. In 

 some instances there is little conge.'^tiou or eruption and for a 

 time the affection is marked, but a great shedding of hairs and 

 dandruff {squamous or scallyform). Itching is usually moderate. 



Diagnosis is to be made from red mange with diflaculty, but 

 the latter affects first the inside of the elbows and thighs, the 

 breast and abdomen, and furnishes no acari on examination, 



