14 



the present state of our knowledge of drawing a hard and fast line of demar- 

 cation between the different sub-orders : indeed, the student of natural history 

 who believes in a theory of evolution, does not expect to meet with any such 

 clearly defined groups. He is interested in rinding what are often called 

 " connecting links," species which bridge over, as it were, the chasm which 

 separates these groups from one another. In cases such as these, experience 

 only, after a very careful examination, will define the natural position of the 

 species, and very frequently this position is a matter of dispute among those 

 who are best qualified to judge of the matter. 



GEODEPH AG A. 



Suppose now that w e have before us a specimen of a beetle, which a refer- 

 ence to the fore-going table shews to belong the first sub-order, the Geode- 

 haga, how are we to proceed in order to find its name and place among its 

 relations ? first, to be quite scientific, we ought to decide whether it belongs 

 to the CicindelidcE or the Carahidcz. These two families are of very unequal 

 size, for while in Britain the former is only represented by one genus with 

 four species, known as tiger-beetles, the latter includes about 62 different 

 genera and several hundred species. The Cicindelidce are characterized by 

 having a little hook, almost like a small claw, attached to the apex of each 

 maxillary palpus, and this hoolc is freely moveable. The Carabida have no 

 such moveable hook or claw. But when once one has seen a tiger-beetle, 

 and one species is common enough over the greater part of England, one 

 need not look for this mark of distinction, as the four species of Cicindela 

 are so characteristic that nothing else among British beetles can be mistaken 

 for them. These species will be differentiated afterwards. 



I will suppose that the student is sufficiently acquainted with the tiger- 

 beetles as to be able to say whether the specimen under consideration does, 

 or does not, belong to it, and if it does not it must belong to the Carahidce. 

 Observe to which of the following groups it belongs, by an examination of 

 the tibiae of the fore-legs : — 



L Anterior tibiae slender, without any notch before the apex. . . Cor abides. 



