86 



Parasitic Arthropods 



and are provided with powerful claws fitted for clinging to hairs. 



The females (fig. 69) measure 1.5 to 2 mm. in length by 1.5 mm. in 



breadth. The male averages a 

 little over half as large. The eggs, 

 or nits, are fixed at the base of the 

 hairs. Only a few, ten to fifteen 

 are deposited by a single female, 

 and they hatch in about a week's 

 time. The young lice mature in 

 two weeks. 



The pubic louse usually infests 

 the hairs of the pubis and the 

 perineal region. It may pass to 

 the arm pits or even to the beard 

 or moustache. Rarely, it occurs, 

 on the eyelids, and it has even 

 been found, in a very few instances,, 

 occurring in all stages, on the scalp. 

 Infestation may be contracted 

 from beds or even from badly in- 

 fested persons in a crowd. We 

 have seen several cases which un- 

 doubtedly were due to the use of 

 public water closets. It produces 

 papular eruption and an intense 

 pruritis. When abundant, there 

 occurs a grayish discoloration of 

 the skin which Duguet has shown 



is due to a poisonous saliva injected by the louse, 



as is the melanoderma caused by the body louse. 

 The pubic louse may be exterminated by the 



measures recommended for the head louse, or 



by the use of officinal mercurial ointment. 



HEMIPTERA 



Several species of Hemiptera-Heteroptera are 69 Phthirius pubi , Ven . 

 habitual parasites of man, and others occur ^Sf 1 *** of female - 



(.A. \&) . 



as occasional or accidental parasites. Of all 

 these, the most important and widespread are the bed-bugs, belong- 

 ing to the genus Cimex (= Acanthia}. 



68. Melanoderma caused by the body 

 louse. From Portfolio of Dermo- 

 chromes, by permission of Rebman 

 & Co., New York, Publishers. 



