Order PARASITICA. 



Under this head come the sucking lice, which are parasitic on warm- 

 blooded animals other than birds. They never become winged, have prac- 

 tically no transformations, the body is more or less flattened and either 

 the feet are scansorial, fitted for climbing and holding, or 

 the mouth hooks are so formed as to enable the insect to 

 anchor itself firmly in place. The insects remain on their 

 host constantly and the eggs are nearly always attached 

 to the hair of the host animal. 



Three species attack man and sometimes cause serious 

 annoyance. In extreme cases an inflammatory condition 

 of the skin may be set up to which the terms "phthiriasis" 

 and "pediculosis" have been applied. 



Almost all the domestic and many of the wild animals are 

 subject to infestation and the list here given will undoubt- 

 edly prove incomplete when systematic collections are 

 made. 



Fig. 29. Head- 

 louse, Pediculits 

 capitis; greatly 

 enlarged. 



Family PEDICULJD^. 



PHTHIRIUS Leach. 



P. inguinalis Leach. The "crab-louse": 

 found in the arm-pits and pubic re- 

 gions of man and sometimes on the 

 coarse hair of the breast. The grasp- 

 ing structures of the feet ,re so we ll 

 developed that it is easier to pull out 

 a hair than to remove the parasite 

 from it. Liberal and repeated appli- 

 cations of mercurial ointment are re- 

 quired to destroy these species. 



Fig. 30. Crab-louse, Phthirius 

 inguinalis; greatly enlarged. 



PEDICULUS Linn. 



P. capitis DeG. The common "head-louse;" more generally found on 

 children. A fine-tooth comb and repeated application of pomade or 

 vaseline will readily control this pest. Tincture, or extract of Lark- 

 spur, has also been used with good effect. 



P. vestimenti Leach. "Body-louse," "clothes-louse" or "gray-back." Lays 

 its eggs in the seams of clothing in which also it hides when not 

 actively feeding. Cleanliness is the best preventive; when an attack 

 is to be dealt with, use mercurial ointment in the seams of the cloth- 

 ing or dip them in gasoline two or three times at intervals of one 

 week. Steaming or thorough boiling will answer the same purpose. 



(85) 



