Trombidi formes 231 



where no hair can be seen to arise even with the aid of a dissecting 

 microscope. It may be mentioned that what appeared to be red blood 

 corpuscles were observed in the oral tube of one specimen." Jameson 

 1948 states that Myobia simplex Ewing has been found full of blood. 

 Skidmore 1934 found Radjordia ensifera (Poppe) (= Myobia ratti 

 Skidmore) causing injury to white rats. He states, "These rats were 

 scratching themselves about the head, nose and neck. Many had small 

 dry scabs on the head, about the ears, and upper sides of the neck. 

 Some had bloody scabs due to bleeding caused by severe scratching." 

 These mites are probably distributed throughout the world. In Aus- 

 tralia Psorergates ovis Womersley, 1941 is parasitic on sheep produc- 

 ing a chronic irritation of the skin along the sides and flanks of the 

 body. The genus Syringophilus contains species which are to be found 

 inside the quills of bird feathers in North America and Europe: they 

 are believed to feed on the internal cones of the feathers. Harpirhyn- 

 chus nidulans (Nitzsch) lives in colonies in the follicles of feathers and 

 causes tumors or cysts in the skin of the host; the mite is to be found 

 on numerous birds including the pigeon. The genus Ophioptes con- 

 tains mites which are parasitic on South American snakes. They live 

 in small pits which they produce in the heavily cornified layer of the 

 snake scales. Ewing 1933 described a species which forms pits in the 

 scales; both Ewing and Sambon described two forms — one is a sack- 

 like nymph without legs, and within this swollen nymphal form is a 

 fully formed, eight-legged individual which Sambon described as a 

 male and which Ewing believed to be a nymph or a female; examina- 

 tion of the type in the United States National Museum shows the form 

 to be an adult but with the sex unknown. The life cycle is otherwise 

 unknown. 



Rejerences: 



Ewing, H. E. 1938. North American mites of the subfamily Myobiinae, 

 new subfamily (Arachnida). Proc: Ent. Soc. Wash. 40(7) : 180-197. 



Grant, D. C. 1942. Observations on Myobia musculi (Schrank) (Arach- 

 nida: Acarina: Cheyletidae). Microentomology 7(3):64-76. 



Jameson, E. W. 1948. Myobiid mites (Acarina: Myobiinae) from Shrews 

 (Mammalia: Soricidae) of Eastern North America. J. Parasitol. 34 

 (4):336-342. 



. 1949. Myobiid mites (Acarina: Myobiidae) from Condylura cristata 



(Linnaeus) Sind Neurotrichus gibbsii (Baird) (Mammalia: Talpidae). 

 J. Parasitol. 35(3) :423-430. 



