378 



THE ANIMAL PARASITES OF MAN 



Rhizoglyphus parasiticus, Dalgetty, 1901. 



The Rhizoglyphii are to be recognised by their short legs, which are beset 

 with spines, and by the tarsi, which terminate in a claw. They live on plants, 

 roots and bulbs, especially the bulbs of lilies. 



This species has been observed on the feet of Indian coolies 

 working in the tea plantations ; they produce a skin disease 



a, b, 



FIG. 242. Rhizoglyphus parasiticus, enlarged ; a, male ; b, female. After Dalgetty. 



which always commences with blebs between the toes, and which 

 almost always extends to the malleoli, but not beyond. The 

 acari have an elliptical body, which is grey, but varies from 

 greenish-yellow to greenish-brown when the stomach is full. Eyes 

 are absent. The legs are composed of five segments and terminate 

 with a claw. The males measure 0*18 mm. in length by 0*08 mm. 

 in breadth, and possess genital and anal pores : the females measure 

 0*2 mm. in length by 0*09 mm. in breadth. 1 



Histiogaster spermaticus, Trouessart, 1900. 



The genus Histiogaster, .which also approaches the Tyroglyphinee , is 

 characterised by the circumstance that the males possess suctorial pores 

 used in copulation, as well as leaf-shaped appendages at the posterior end 

 of the body. They feed on vegetables, especially on small fungi. 



1 Dalgetty, A. B., "Water-Itch; or, Sore Feet of Coolies" (Journ. Trop. Med., 

 1901, iv., p. 73). 



