422 THE MALLOPHAGA. 



species which commonly attach themselves to man, 

 one is always found amongst the hairs of the head, 

 and the second amongst those of the body and face, 

 whilst the third takes up its quarters in the clothes, 

 and that the fourth species is described as appearing 

 occasionally in such numbers upon some unhappy 

 patient, as to give rise to a peculiar disease, called 

 phthiriasis by the ancients, which appears to have 

 frequently ended fatally. 



If we turn to the second order, that of the 



Mallophaga^, 



we find it also composed of parasitic insects, but these 

 we can look at without any personal feelings, as none 

 of them infest the human species. They differ from 

 the true Lice in having a regular biting mouth, fur- 

 nished with hooked mandibles, and usually with max- 

 illae and palpi, and closed above and below by a labrum 

 and labium. They are parasitic upon different species 

 of Mammalia and Birds, but principally on the latter, 

 and from this circumstance the name of Bird-lice is 

 commonly applied to them. So numerous are they 

 in many cases, that the skins of birds may be found 

 almost covered with them in particular spots; they 

 do not, however, suck the blood of the animals which 

 they infest, but content themselves with devouring the 

 most delicate parts of the down or feathers with which 

 their hosts are covered. As amongst the Anoplura, 

 each species of these parasites is usually confined to 

 some particular animal as its peculiar victim, and as 

 nearly every species of Bird is infested by at least one 

 of these parasites, the number of species is by no 

 means small. 



* Gr. mallos, wool ; phago, to eat. 



