PHTHIEIUS PUBIS. 83 



bears thick, brown, irregularly disposed stumps, and oil her dorsal 

 surface smaller ones more sparingly distributed. The unequal, 

 elongated legs are walking feet in front, gradually narrowing to 

 the cylindrical, unemarginate tibiae, which have a small tooth, 

 and on the tarsus attached to them a small, nearly straight claw. 

 But behind they are thick, powerful scansorial feet, the tibise of 

 which are large, bell-shaped, indented at the extremity, and some- 

 what in front upon the inside have a large tooth, furnished with 

 a small, straight, chitinous stump and a bristle ; the tarsus is 

 long, crooked, one-jointed, horny, and bears a large horny claw, 

 which turns back upon the tooth of the tibia like a pair of nippers. 

 This claw is always very massive, but rather blunt than acute 

 anteriorly and towards the free extremity. It is seen distinctly 

 that its inner margins are toothed and that it is hollow interiorly. 

 To the interior of its base there pass two short, strong muscles, 

 which give the tarsal joint the appearance as if it bore a bell 

 (without a clapper) in its interior. 



The reproductive organs are not quite clear to me, as I 

 have only been able to examine females. Leuckart says of the 

 eggs that they are considerably smaller than those of the common 

 louse ; but, in other respects, exactly similar to them, except 

 that the annular ridge, which surrounds the infundibular entrance 

 into the micropylar canal, is very much wider than in the 

 common louse (" in diameter), and the operculum presents a 

 wide lattice work, formed by radiating processes. 



The crab-louse lives on the hairy regions of the body, especially 

 about the pubis, but when it increases excessively, also amongst 

 the hairs of the chest, the eyebrows, the eyelashes, 1 but never in 

 the head. It bites deeply and firmly into the skin, producing 

 violent itching, and lives on the human blood. It is transferred 

 to other individuals by long contact, and by the agency of clothes, 

 linen, and beds. It is most abundant in the south. 



Schultz, with certain classes of people, regard the lice as 

 beneficial to the animal economy ; carriers cherish them in order 

 to put one under the prepuce of their horses when they cannot 

 make water. 



Therapeutics. As the crab-lice are endemic in certain districts, 

 we must be particularly careful there. The treatment is the same 

 as with the other lice. I have cured a patient who had long 



1 In Dalrymple's ' Pathology of the Human Eye,' London, 1852, is a drawing (PI. VI, 

 fig. 6) of an eyelid with groups of these lice upon it. 



