142 
MODEllN SVSTElf. 
placed in an order which he named Farasita. This name Dr. Leach 
has changed for the sake of harmony, and also to render the name 
more easy ot retention in the memory, the characters being drawn 
from the same parts. 
Their motion is slow, and their nourishment is derived from the 
blood of mammalia, birds and insects. 
“It is almost an established fact, that every species of bird (and 
probably mammiferous animal) has its own peculiar parasite; and 
there is no instance of the same species of louse having been ob- 
served on two distinct species of birds, although some birds (as the 
raven oyster-catcher, &c.) are infested with several species of para- 
sites.” The importance of clearly ascertaining the truth is such to 
the ornithologist, that Dr. Leach has employed a considerable por- 
tion of time for the purpose of investigating and of describing the 
species with accuracy, little more than a bare catalogue of names 
and habitats having been given in the works of Linne, Fabricius, 
and Gmelin. The result of his examinations he does not consider 
himself as able to communicate at present; but it is his intention, 
when the subject has arrived at maturity, to give a paper on this Ol- 
der to the Linnean Society of London. 
Fam. I. PEDicutiDiE. Leach. 
Mouth consisting of a tubulose, very short haustellum. 
•Genus 6. PHTHIUUS. Leach. Pedicelcs. Linn., Redi, Latr., 
Pabr. 
Anterior pair of feet simple; two hinder pair didactyle: thorax extremely 
short, scarcely visible. 
Sp. 1. Phth. inguiualis. Body whitish. 
Pediculus inguiualis. Redi. Pediculus pubis. Linn., Fair., Latr. Le 
Morpion. Geoff. Phthirus inguiualis. Leach. 
Inhabits the eyebrows, Sec. of men and women, being commonly 
known under the titles Crabs, Crab-lice, &c. 
Genus 7. PEDICCL.. -S. Linn., Fair., Do Geer, Geoff., Redi , 
Hermann, Lam., Leach. 
Feet all armed with a finger and thumb : thorax composed of three di- 
stinct equal segments. 
Sp. 1. Fed. humanus. Body oval, lobate, white and nearly immaculate. 
Pediculus humanus. Fair., Linn., Latr., Leach. 
Inhabits the bodies end garments of men, and is known by the name 
of the body-louse. On the continent of Europe, especially in Spain 
and Portugal, it is very abundant. In Britain it is of rare occur- 
rence, and may have been introduced from the neisihbourino- coun- 
tries. ° ° 
