THE BRITISH GEODEPHAGA. 15 



hooked jaws articulated at their bases to the sides of the head, 

 and worked by powerful muscles. They are of various forms, but 

 those in the examples selected are as typical as any. It will be 

 noticed that the mandibles are not alike, the one on the left-hand 

 side being longer than that on the right ; also, that the right-hand 

 mandible has a deep notch at about half way down, whilst the other 

 has only a very small notch near the bottom (see/^, in Fig. 9). 

 The use of these notches is evident ; they act, in fact, like a pair 

 of garden-shears, where the notch in one blade holds the branch or 

 other material whilst the other shears it off. The tips of the man- 

 dibles act more like canine teeth. The mandibles are always 

 strengthened by being very much thickened towards their outer 

 sides, and their cutting-edges are tipped with specially hard 

 chitine. 



Under the mandibles is the other pair of jaws, or maxillce^ 

 composed of several parts : first, the cardo, or hinge, attached to 

 which is the stipes, or stalk, and the palp if er, which carries the 

 palpi, composed of four joints, and on its inner side the inner 

 palpiform lobe, which is like a palpus of two joints. Here we 

 have the distinctive character of the section Adephaga. In all 

 other sections, although variously modified, this lobe is not of a 

 palpiform shape, and is more or less clothed with bristles, so as to 

 look like a brush. Also attached to the stipes is the lacinia, or 

 blade, terminating in a sharp hook. This blade is always fringed 

 with a series of bristles^ the use of which seems to be to prevent 

 the escape of the food from the mouth sideways during the 

 process of mastication. 



It may be useful to superficially examine the mouth of one of 

 the Brachelytra by way of contrast, and for this purpose I think 

 " Ocypus olens'^ or "The Devil's Coach-horse" (Figs. 10, 11, and 

 12), a very suitable example, as it is typical of the section and 

 is a carnivorous beetle. It will be noticed that the inner palpi- 

 form lobe {g.g., Fig. 12), which is the distinctive feature of the 

 Geodephaga, is here much shortened, and becomes a compact brush. 

 This is the most important characteristic, but there are many other 

 points of interest, such as the large, square, flat head, deeply-cleft 

 labrum, straight mentum, without any emargination or tooth, 

 emarginate ligula, short palpi, and long hooked mandibles, which 



