Transactions oftheLinnean Society. 279 



importance. It is from the pen ofW. S. MacLeay, Esq. " On the 

 structure of the Tarsus in the Tetramerous and Trimerous Cole- 

 optera of the French Entomologists." The facts which it de- 

 velopes are adapted to demolish the very foundation of the pro* 

 fessedly natural arrangement of the Coleoptera^ which has been 

 so generally followed since its adoption by Latreille. Mr. Mac 

 Leay had long since pointed out many anomalies in the number 

 of the joints of the tarsus, by which certain genera were appa- 

 rently excluded from any of the sections to which the names of 

 Pentamera, Heteromera^ Tetramern^ Trimera^ Dimera, and 

 Monomer a^ have been applied. The affinities of most of them 

 were, it is true, so evident, as to enable the entomologist to place 

 them at once in their appropriate situations ; but in doing so he 

 assumed the existence of a character which was not to be found in 

 them, and even in some instances acted in open defiance of the 

 system, as in the case of the genus IleteroceruSy a tetramerous 

 group, which he nevertheless continually arranged among the 

 Pentamera. A system admitting and even requiring such exten- 

 sive deviations from the principles on which it rests, must of nt 

 cessity be erroneous ; it is evidently not natural, and may be left 

 to the fate of all artificial methods, to be employed or rejected as 

 convenience dictates. Still more indisputably will this appear, 

 K when it is shown, as in the present paper, that no such section as 

 W the Trimera exists in nature, and that the great majority of the 

 y Tetramera are in reality Pentamerous. A close examination of 

 any Linnean Cerambyxj CurcuUoy or Chrysomela^ will show, that 

 its tarsi consist of five articulations instead of four, as assumed in 

 the tarsal system of the French entomologists, the joint which 

 they have described as terminal being in reality composed of two 

 distinct pieces, the first of which is very small. The correspond- 

 ing joint in the tarsi of the Coccinellce will be found to be divided 

 in a similar manner, and therefore what have been considered as 

 Trimera^ are actually Tetramera. An arrangement grounded on 

 data so erroneous cannot be natural, and it has here received a 

 shock which it can scarcely withstand. The field is now thrown 

 open for a better classification, founded on a more correct basis. 

 We wait with impatience for its appearance. The exposition of 



