132 Accidental or Facultative Parasites 



Tyroglyphus siro, and related species, have been found many- 

 times in himian feces, under conditions which preclude the explana- 

 tion that the contamination occurred outside of the body. They 

 have been supposed to be the cause of dysentery, or diarrhoea, and 

 it is probable that the Acarus dysenterim of Linnsus, and Latreille, 

 was this species. However, there is little evidence that the mites 

 cause any noteworthy symptoms, even when taken into the body 

 in large numbers. 



Histiogaster spermaticus (fig. 152) is a Tyroglyphid mite which 

 was reported by Trouessart (1902) as having been found in a cyst 

 in the groin, adherent to the testis. When the cyst was punctured, 

 it yielded about two ounces of opalescent fluid containing spermatozoa 

 and numerous mites in all stages of development. The evidence 

 indicated that a fecundated female mite had been introduced into 

 the urethra by means of an unclean catheter. Though Trouessart 

 reported the case as that of a Sarcoptid, Banks places the genus 

 Histiogaster with the Tyroglyphidae. He states that our species 

 feeds on the oyster-shell bark louse, possibly only after the latter is 

 dead, and that in England a species feeds within decaying reeds. 



Nephrophages sanguinarius is a peculiarly-shaped, angular mite 

 which was found by Miyake and Scriba (1893) for eight successive 

 days in the urine of a Japanese suffering from fibrinuria. Males, 

 .117 mm. long by .079 mm. wide, females .36 mm. by .12 mm.^ 

 and eggs were found both in the spontaneously emitted urine and in 

 that drawn by means of a catheter. All the mites found were dead. 

 The describers regarded this mite as a true endoparasite, but it is 

 more probable that it should be classed as an accidental parasite. 



Myriapoda 



There are on record a number of cases of myriapods occurring as. 

 accidental parasites of man. The subject has been treated in detail 

 by Blanchard (1898 and 1902), who discussed forty cases. Since 

 then at least eight additions have been made to the list. 



Neveau-Lamaire (1908) lists thirteen species implicated, repre- 

 senting eight different genera. Of the Chilognatha there are three, 

 Julus terrestris, J. londinensis and Polydesmus complanatus . The 

 remainder are Chilopoda, namely, Lithobius forficatus, L. malenops, 

 Geophilus carpophagus, G. electricus, G. similis, G. cephalicus, Scutigerc^ 

 coleoptrata, Himantarium gervaisi, ChcBtechelyne vesuviana and 

 Stigmatogaster subterraneus. 



