PEDICULUS 



755 



Genus Pediculus Linnaeus, 1758. 



Definition, — Pecliculinae with distinct neck and thorax narrov/er 

 than abdomen. Legs all strong with strong claws. Thumb-like 

 projection of the tibia long, thin, and covered with bristles. Abdo- 

 men long and narrow, with segments not compressed together, and 

 without lateral hook-like processes on the fifth to eighth .segments. 

 Two-jointed telson carries ventrally a pair of eone-like processes. 

 Female gonopodia clamp-like and bent inwards. 



Classification. — Only four species are at present assigned to the 

 genus Pediculus: — 



P. humanus Linnaeus, 1758, found on man. 



P. corporis de Geer, 1778, found on man. 



P. punctatus Rudow, 1869, found onPos grunniens. 



P. consobrimts Piaget, 1880, found on Aieles pentadactylus. 



There is a doubt as t o whetherP. pimctaUis is really a pediculus, and 

 P. consohriniis is said by Neumann to 

 be indistinguishable from P. humanus, 

 therefore the species are reduced to 

 two : — 



P. humaims Linnaeus, 1758. 

 P. corporis de Geer, 1778. 



These are very alike, and have been 

 thought to be only varieties of one 

 another. Interbreeding seems to be 

 possible. The following points may 

 help to differentiate them: — 



1. Found on the human head, 



with well-defined abdominal 

 segments marked by a fes- 

 tooned lateral border — 

 P. humanus. 



2. Found in the clothing, larger 



than P. humanus, with 

 broader thorax and lateral 

 borders of abdomen less 

 festooned, and segments not 

 quite so distinctly indicated 

 — P. corporis. 



Fig. 368. — Egg of Pediculus 

 humanus Linn^us, 1758, 



ATTACHED TO A HaIR. (X 35 



Diameters.) 



(From a photograph by 

 J. J. Bell.) 



Pediculus humanus Linnaeus, 1758. 



Synonyms. — Pediculus humanus var. i Linnaeus, 1766; P. humanus 

 var. capitis de Geer, 1778; P. cervicalis Leach, 1817; P. capitis 

 Nitzsch, i8i8;P. humanus Csiki, 1904; P. nigritarum Latreille. 



Definition. — Pediculus often varying in colour somewhat accord- 

 ing to the human race, on which it is parasitic, with thorax often 

 narrowing distinctly anteriorly, well-defined abdominal segments 



