1 88 ARACHNOIDEA, 



CASE use in arriving at a correct view of their natural relations to each 

 other. Notwithstanding this, we shall for the sake -of facilitating 

 the task of any one who may be disposed to make ia, study of the 

 family, give, in their natural places, a figure of each of Koch's 

 genera above mentioned. . There see'ms to be at least three 

 pretty well defined types of form. The oblong oval one that 

 we have in this country, and v/hich extends over the whole of 

 the northern temperate regions, which may be regarded as the 

 true Ixodes, the more orbicular species like a coin, generally with 

 eyes, almost exclusively tropical, and principally composed of 

 Koch's genus Amblyomma, and the small, very flat variegated 

 species, which as yet have only been found on snakes. 



The Ixodidse that we have in this country live in woods and 

 herbage, and attach themselves to different animals as they pass ; 

 from sucking the blood, the body of the female swells in the form 

 of a pea or bean. It has indeed often been supposed that they 

 are actually parasitic* on the animals on which they are found, and 

 that a separate kind is appropriated to each animal, and that they 

 breed either upon them or about them. Thus, one is called the 

 dog-tick, another the cattle-tick. One of the American represen- 

 tatives is called the ox-tick (Ixodes bovis), and Leach described 

 six British species, one as being appropriate to the swallow, 

 another to the hedgehog, two to dogs, another to dogs and hedge- 

 hogs, and a sixth (Nycteribia), which turns out to belong to another 

 order (the flies), to the bats. It is an undoubted fact also, that 

 vast numbers of the present species have been found in dog-kennels, 

 swarming so in the chinks of the wood, as to render it necessary 

 to pull them down and burn them. Nothing, however, in this is 

 inconsistent with the natural habitat of the ticks being in herbage 

 and foliage, or with their being carried by dogs or cattle from, their 

 proper habitat to the places where they live, and there propagating 

 themselves. 



There is no getting over the fact, which every one accustomed 

 to a country life knows, that dogs will go out in the morning 



