CHAPTEK VI. 



PARASITES FREE DURING THEIR WHOLE LIFE. 



This first category of parasites includes all those which 

 are not enclosed, and which live at the expense of others, 

 without losing the attributes and advantages of a wan- 

 dering life ; they are as free as the vulture or the falcon 

 which pursues its prey. We shall not, however, include 

 among them the parasitical kite of Daudin, which tears 

 from the hands of the traveller a piece of the flesh 

 which he is preparing in the open air, nor the small 

 Egyptian plover, which keeps the teeth of the crocodile 

 clean. The former is a pirate, a highway robber; the 

 plover, on the contrary, is a kind neighbour, an attend- 

 ant who performs valuable services. 



We are more correct in considering as parasites the 

 Vampires (Phyllostoma) , those audacious bats of South 

 America, which settle on the sleej)ing traveller or his 

 beasts, and suck their blood by means of the sharp pa- 

 pillae of their tongue. These animals are winged leeches 

 which bleed their victim and pass on. We place among 

 free parasites the greater part of leeches, some in- 

 sects, and a certain number of arachnida, crustaceans, 

 and infusoria. 



As we have mentioned free messmates, so we have 



