EXTERNAL ANATOMY OF INSECTS. 689 



individual joints it may be said in general that they are 

 rather triangular, with an anterior sinus for the reception 

 of the succeeding joint: the first joint usually departs most 

 from this form; in the bees it is commonly much larger 

 than the rest, especially in the last pair of legs, and nearly 

 forming a parallelogram a ; in Euglossa it is trapezoidal; in 

 the majority nearly linear or filiform. With regard to 

 their termination — in Brachycerus and some ants (Ponera, 

 Myrmica, &c, Latr.) the three Jirst joints; in Dascillus, 

 Lycus reticulatus and affinities, the third and fourth ,• and 

 in the great majority of the Tetramerous insects the 

 penultimate joint is bilobed; although in most Predaceous 

 beetles this joint is entire or simply emarginate, yet in 

 Colliuris h terminates in a single oblique lobe; and in 

 Lebia, Drypta, &c, it is nearly bipartite. I must now 

 advert to the Ungula or claw-joint: it is usually clavate 

 or thickest at the end and curved ; but in the Asilidce it 

 is shaped like a vase or cup ; in Phanams, in the four 

 posterior tarsi, in which the claws are obsolete, it is 

 thickest at the base and sharpest at the extremity 13 ; it 

 usually forms an angle with the rest of the tarsus, rising 

 upwards, which enables the insect to move more easily 

 without hindrance from the claws, and also more readily 

 to lay hold of any object it meets with ; but in the La- 

 mellicorn beetles and many other insects it is in the same 

 line with it. As in the beetles last mentioned this joint 

 is often inserted in the extremity of the preceding one; 

 but in CEdemera it articulates with the middle of its 

 upper surface; and in Lycus and a numerous host of 



a Mon. Ap. Angl. i. t. xii. neitt.f. 20. 

 b Plate XXVII. Fig. 44. r. 

 VOL. III. 2 Y 



