66t EXTERNAL ANATOMY OF INSECTS. 



in Necrophorus they are the smallest : — though almost 

 universally without articulations, in Galeodes the clavicle 

 consists of two and the coxa of three*. 



b. Trochanter or Scapula b . This is the second joint 

 of the leg: and if the coxa is regarded as the analogue of 

 the thigh in vertebrate animals, this should seem to re- 

 present the patella or rotula, vulgarly called the knee- 

 pan. Latreille and Dr. Virey consider this articula- 

 tion as merely a joint of the coxa c ; but if closely exa- 

 mined, especially in Coleopterous insects, you will find 

 it so fixed to the thigh as scarcely to have separate mo- 

 tion from it, and in many cases it seems to be merely its 

 fulcrum ; but I am not aware that any instance occurs in 

 which it has not motion separate from that of the former 

 joint. 



As to its artictdation with the coxa, — in the Cole- 

 optera it appears to be of a mixed kind; for it inoscu- 

 lates in that joint, is suspended by ligament to its ori- 

 fice, and its protuberances are received by correspond- 

 ing cavities in it ; and its cavities receive protuberances, 

 which belongs to a ginglymous articulation. I have 

 observed two variations in this Order, in one of which 

 the motion of the thigh and trochanter is only in two di- 

 rections, and in the other it is nearly versatile or rotato- 

 ry. The Lamellicorns afford an example of the first, and 

 the Bhyncophorons beetles or weevils of the second. If 

 you extract from the coxa the thigh with the trochanter 

 of the larger species of Dynastes M C L., you will find that 

 the head of the latter is divided into two obtuse incurv- 



3 L. Dufour, Descr. des six Arachn. &c. : Annates Generates, &c. 

 J 820. 19. t. lxix./. 7. d, b Plate xiV. XV. XXVII. q'„ 



c N, Diet. a" Hist, Nat. xvi. 195. xxvi. 157. 



