756 



MALLOPHAGA AND ANOPLURA {LICE) 



marked by lateral festoons. Thumb-like projection on the tibia 

 armed with a spine. Habitat, homo. 



Rem ar lis, —This is the head-louse, which is cosmopolitan in distribution, 

 but varies in colour on the different races, as was pointed out by Murray, 

 being very dark on African negroes and Tamils, and said to be yellow on Chinese 

 and Japanese, and orange on Hottentots. 



On Europeans it is light grey in colour. Daniels says that the pediculi of 

 Chinese do not pass readily to Tamils ; though in our experience the pediculi of 

 native servants, Sinhalese and Tamils, will pass to Europeans. 



These pediculi are extremely common in the tropics, and it is an ever}''- 

 day scene to witness natives busy at work killing them on their friends' heads. 



Morphology. — The head-louse is about 2 millimetres in length by i milli- 

 metre in breadth. The female is larger than the male, and exists in greater 

 numbers. The head is triangular, the thorax .^road with short legs, and the 

 margins of the abdomen are dark. 



Fig. 369. — Pediculus corporis de Fig. 370. — Pediculus corporis de 



Male. — The posterior somite is rounded off and prominent, with a circular 

 opening dorsally, which is the common aperture of the genital and alimentary 

 canal. The penis is simple, wedge-shaped, and is usually seen protruding 

 dorsally. 



Female. — The last abdominal segment is deeply notched at the apex, where 

 the anus is situated. The vagina opens on the ventral surface. 



Life- History. — The female lays fifty to sixty eggs, which are attached firmly 

 to the hairs by the secretion of the cement gland. In about six days these 

 eggs hatch. The young pediculi becom^^ fully developed in fourteen to twenty 

 days. 



Pathogenicity. — It can carr}?- typhus and produce a form of impetigo. 

 Treatment. — White precipitate ointment or common paraffin oil may be 

 used. 



Geer: Male. (X25.') 



Geer: Female. (X25.) 



