142 ANIMAL PARASITES AND MESSMATES. 



place, and becomes of such a monstrous size that the 

 entire insect is nothing more than an appendage of the 

 abdomen, as may be seen in the annexed figure. This 

 insect is well known, since it attacks man, and usually 

 establishes itself on his toes, but it occasionally fixes 

 itself in the same manner on the dog, the cat, the pig, 

 the horse, and the goat. It has also been seen upon the 

 mule. Mons. Guyon has paid much attention to it, but 

 we owe the last observations to Mons. Bonnet, a French 

 navy surgeon, who passed three years in Guiana, and 

 has ascertained that the chigoe fortunately does not 

 extend beyond the 29th degree of south latitude. Another 

 parasite, well known by sportsmen, is the tick. It is not 

 an insect like the flea, but an arachnid, a kind of acarus, 

 which passes through its last stages of development 

 under the skin of a mammal. It is called Ixodes ricinus, 

 and Professor Pachenstecher has carefully studied its 

 organization. The ticks especially attack dogs, but are 

 also found on the roebuck, the sheep, the hedgehog, and 

 even on bats. 



Some years ago it was propagated in an extraordinary 

 manner on roebucks in the woods of the Duke of Aren- 

 burg, in the environs of Louvain. They are sometimes 

 found also on man. We know of two instances : the first 

 is that of a lady at Antwerp, who had a small tumour on 

 her shoulder, which was removed, and enclosed a living 

 tick. Leeuwenhoek gives an instance of a woman of the 

 lower classes who had a tick in the middle of her stomach. 

 Moquin-Tandon relates that Easpail found some on the 

 head of a little girl four or five years old. He also gives 

 an instance of a young man who, returning from hunting, 

 found a tick under his arm; and while on the site of a 



