Spiders and Their Near Relatives 



Superfamily SARCOPTOIDEA (Sar-cop-toi'de-a) 



The Itch-mites and Others 



The Sarcoptoidea include seven families of mites; but 

 several of these families are small and include only forms that 

 are not likely to attract the attention of the ordinary observer. 

 Some of these forms, however, are of great scientific interest, as 

 for example Pediculoides, which lives parasitically upon insects, 

 and which gives birth to sexually mature young. 1 1 is in one of the 

 families of this group, the Tyroglyphidae, that those mites that 

 have the remarkable migratory stage, the hypopus, described on 

 an earlier page, are found. It is to this family also that belong 

 certain species which attack food products as cheese, sugar, flour 

 and dried meats; these are often of considerable economic impor- 

 tance. The disease 

 iV J/ 1 /a known as " grocers' 



itch" is caused by 

 these mites which 

 sometimes spread 

 from infested ma- 

 terials to the hands 

 of those handling 

 them. 



To the family 

 Sarcoptidae belong 

 the itch-mites, 

 which are so-called 

 because they often burrow within the skin of man, causing the 

 disease known as the itch. The diseases of domestic animals 

 known as scabies or mange are also due to members of this 

 family. 



The species attacking man is Sarcoptes scahei (Sar-cop'tes 

 sca'be-i) (Fig. 66). It is apt to infest the soft skin between 

 the fingers and may spread to other parts of the body. The 

 mites make burrows within the skin and the eggs are deposited 

 within the burrows. The spread of the disease is due to the 

 spreading of the mites from one person to another; this is often 

 brought about by hand-shaking. The remedy most often used 

 is a sulphur ointment, by means of which the mites can be killed. 

 The disease known as sheep-scab is caused by the mite 



Fig. 66. SCARCOPTES SCABEI 



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