Trombidiformes 237 



presence of the mite distinguishes this mange from sarcoptic mange 

 or fungus infections. D. equi RaiUiet, aUhough present on horses free 

 of any disease, can also cause a "pathological condition of the skin, 

 characterized either by pruritus, varying greatly in intensity, or by 

 definite lesions. The coat is poor, with the hair very sparse in places." 

 The disease usually commences on the saddle or neck of the animal 

 but does not appear to be infectious. In the advanced stage pustules 

 are present and the skin thickens. D. phylloides Csokor "causes a pus- 

 tular skin disease in pigs, the pustules varying from the size of a grain 

 of sand to a walnut." "Sometimes they may become confluent, and 

 may rupture and cause sores and ulcers on the skin." They are to be 

 found only where the skin is fine in texture, spreading "from the snout 

 over the neck and under part of the chest and abdomen, and over the 

 flanks and inner parts of the legs." Usually the general health of the 

 animals is not affected. D. bovis Stiles causes nodules or pustules in 

 cattle, these pustules varying in size from a head of a pin to as large 

 as a hen's egg. They are to be found around the ears, sides, shoulders, 

 and intercrural space. Various stages of development are to be found 

 in the cheesy or fluid contents of the nodules. The disease appears to 

 be infectious but does not seem to affect the general health of the ani- 

 mal. However, holes caused by these mites reduce the value of the 

 hides. Other species have been found on sheep, hedgehogs, field mice, 

 cats, rabbits, voles, and rats and are probably to be found on many other 

 hosts. 



References: 



Hirst, S. 1919. The genus Demodex Owen. Brit. Mus. (Nat. Hist.) 



Studies on Acari No. 1. 

 . 1922. Mites injurious to domestic animals. Brit. Mus. (Nat. Hist.) 



Econ. Series No. 13. 

 Lombardini, G. 1942. Contributo alia conoscenza della morfologia dei 



Demodicidae. Chiave analitica del genere Demodex Owen. Redia 28: 



89-102. 



Erythraeidae Oudemans, 1902 



Figures 176, 177 



Diagnosis: The adults of this family are reddish, predaceous mites 

 with legs adapted for running. The larvae are heteromorphic, lack 

 urstigma, and are parasitic on arthropods. The adult body is oval and 



