SOME HUMAN PARASITES 315 



Instances are not uncommon in which infestations of this 

 insect have been contracted by using a public water-closet. 

 The danger of unclean lodging houses and public bath 

 tubs needs hardly be mentioned. Moreover, this species 

 reproduces more rapidly than the others and sometimes 

 causes serious affections, although older accounts of these 

 have probably been greatly exaggerated. The eggs, which 

 are pear-shaped, are attached to the hairs. They hatch in 

 six or seven days and in fifteen days the young lice are 

 ready for reproduction. 



The presence of the lice causes a severe itching followed 

 by reddish inflamed spots over the regions of the body 

 infested. If allowed to go on undisturbed, more serious 

 affections take place. 



Stiles gives the following synonymy for these species of 

 human lice : — 



The head louse : P. humanus Linnaeus, 1758; 



P. capitis de Geer, 1778 ; 



P. cervicalis Latreille, 1803. 

 The body louse : P. corporis de Geer, 1778 ; 



P. vestimenti Nitzsch, 1818 ; 



P. tabescentium Alt, 1824. 

 The crab louse : Pediculus pubis Linnaeus, 1758 ; 



P. inguinalis Reichard, 1759 ; 



Phthirius inguinalis (Reichard) Leach, 1815; 



Phthirius pubis (Linnaeus, 1758) Kiichenmeister, 

 1855. 



Methods of controlling these lice. — First of all absolute 

 cleanliness is a prime requisite in keeping free from these 

 parasites. In case of the body louse, the clothes must be 

 steamed or cleaned by immersing and soaking in gasoline. 

 Two treatments of gasoline should kill the lice and eggs. 



