COLEOPTEROUS INSECTS. Ill 



the joints is most commonly triangular or elongate- 

 quadrate. On the under side they are usually densely 

 clothed with hairs or bristles forming a kind of cush- 

 ion, which enables the insects to make their footing 

 more secure. The tarsi terminate in two curved 

 claws, which in some instances are double, and in 

 others are bifid at the tip. They are frequently 

 serrated on the under side. 



As the anterior pair of legs are in most cases con- 

 vertible into organs of prehension, they sometimes 

 exhibit striking peculiarities in their structure in 

 order to adapt them to this usage. In several 

 species they are remarkably elongated, and occa- 

 sionally provided with a kind of hook at the extre- 

 mity of the tibia, as in the harlequin beetle, repre- 

 sented on Plate XXV. In other instances, as among 

 some of the predacious Carabid<c> the anterior ti- 

 biae have a deep notch on the inner side towards 

 the apex, above which there is placed a strong 

 moveable spine, which admits of being pressed 

 down across the opening, and thus secures any 

 object that may happen to be within it. A scarce 

 British beetle, found on the coast of Norfolk, and 

 on the shores of the Frith of Forth near Portobello 

 ( Cillenwn laterale) y &hows an arrangement of this 

 kind ; and it is rendered still more efficient by the 

 addition of two small spines on the side of the notch 

 opposite to the moveable spine, which receive the 

 latter between them when it closes, and prevent it 

 f-om being twisted in a lateral direction (fig. 1 of the 



