NEPHROPHAGES 729 



Female cylindrical, 0-2 by 0*07 millimetre; becomes much distended pos- 

 teriorly when gravid. 



Life-History. — They live on the stalks of cereals, and feed on animal and 

 vegetal juices. The adult hatches directly from the egg. 



Pathogenicity. — They cause diffuse erythema, urticaria, and itching. 



Nephrophages Miyakeand Scriba, 1893. 

 Nephrophages sanguinarius Miyake and Scriba, 1893. It is a very doubtful 

 parasite of man; it was found in bloody urine passed by a man in Japan. 



SUBORDER V. ASTIGMATA. 



This suborder includes the superfamily Sarcoptoidea. 



SUPERFAMILY SARCOPTOIDEA. 



Astigmata with small three-pointed palpi adhering for some distance to 

 the hypostome, with usually ventral suckers. Two families concern us — 

 (i) Tyroglyphidae, {2) Sarcoptidae. 



Fig, 346. — Tyroglyphus longiov Fig. 347. — Tyvoglyphus longior 



VAR. castellanii Hirst, 1912: var. castellanii Hirst. 1912: 



Dorsal Aspect. Ventral Aspect. 



Family i : Tyrogl yphid^. 



Very small mites without eyes; only accidental parasites being found in 

 flour, sugar, cheese, etc. 



Tyroglyphus Latreille, 1796. — With smooth dorsum; cep halo thorax with 

 four long bristles and no stout spines on tarsi ; with claws and suckers. Aleuro- 

 hius farincB (De Geer) in corn may get into the skin. They are the cause 

 of so-called vanillismus. According to Theobald, Linnaeus reported a case of 

 dysentery as being due to this species {A cams dysenteric^) . 



Tyroglyphus siro Linnaeus, 1758, is supposed to be the cause of vanillismus, 

 and T. longior Gervais, 1844, is found accidentally in faeces, urine, or pus. 



T. longior var. castellanii Hirst, 191 2, was found by Castellani in copra and 

 on people affected by copra itch in Ceylon. In this variety, in contrast to 

 T. longior, there is no pair of short hairs on the ventral surface, behind the anal 

 suckers. 



GlyciphagUS Hering, 1838. — With dorsum covered with hairs. 

 G. prun or um Her m3.nn (synonym, G. domesticus de Geer, 1808) is the cause 

 of grocer's itch. 



Rhizog^yphus Claparede, 1869 — R. parasiticus Dalgetty, 1901. — With short 

 legs, armed with spines. Tarsi end in a claw. Live on plants. 



