8 



GENERAL PRINCIPLES. 



10. 



III. Great caution must be exercised in the naming of different 

 parts in the several orders, as, frequently, the same organ in the 

 different groups takes a very different form. If particular names 

 were applied to such modifications, it would tend to mislead, by giving 

 the appearance of different parts to one and the same. Nor is the 

 reverse of this admissible, for different organs must not bear the same 

 name *. 



11. 



IV. The names of parts should be derived, in prefereuce, from 

 Latin, but it is advisable in those parts which have always been 

 signified by Greek terms, to retain them, and introduce new Greek 

 ones whenever new parts are discovered within the limits of the 

 particular organs f . 



V. Peculiar organs, which, nevertheless, can only be considered as 

 variations of a long known typical form, are best distinguished by an 

 adjective expressive of the peculiarity. 



E. g. The legs are called pedes; when adapted to the seizing of prey 

 they are suitably called pedes raptorii,not arms (brachia) according to 

 Kirby. The idea of arms presumes a certain organisation which is 

 never found in insects, although the raptorious legs of insects may 

 possibly be analogous in their functions. But it is certainly incorrect 

 to call the anterior legs of insects in general arms; we might just as 

 rationally call the fore legs of quadrupeds arms. Swimming legs are 

 thus called pedes natatorii, but not fins (pinnae). 



* Fabricius made a mistake of this kind, in applying to what he had called truncus, in 

 the Coleoptera, the name of thorax, in the Hymenoptera and Diptera ; and, in calling by 

 the latter term the anterior portion only of the same part, in the Coleoptera, Hemiptera, 

 and Orthoptera. As in each of the orders of insects, the thorax consists of three parts, 

 which have been distinguished as prothorax, mesothorax, and metathorax, it is evidently 

 incorrect to call that collare, in the Hymenoptera, which is called prothorax in the 

 Coleoptera, Hemiptera, and Orthoptera ; for the same orismology must be applied to every 

 order. Reasoning upon the same principle, we cannot see why that portion of the head 

 should be called hypostoma, in the Diptera, which, in the other orders, has long been 

 indicated by the name of clypeiis. 



| It consequently appears preferable to us to call the first segment of the thorax the 

 prothorax, rather than collare, exclusive of the greater precision and comprchensibility ot 

 llu- first term. 



