121 



The first group (with the front elevated) is the most normal form, and shows an 

 unbroken series ; Metopias, with its immarginate abdomen, being the inosculating 

 point with Batrisus, which, by slight variations in the form of its front, shows its ten- 

 dency towards the typical stem. 



The second group requires more careful analysis. The curious sculpture on the 

 thorax of many of its members is not found in the first group, and should lead us to 

 suspect that it may be the connecting chain with other forms. The embryonic cha- 

 racter is plainly seen in the elongate form, and six-articulated abdomen of Euplectus ; 

 while in the other series, Adranes, though of very low organization, preserves the typi- 

 cal Pselaphus form. Of the two genera in this second series, Hamotus is plainly a 

 Bryaxis form, while Faronus is a Euplectus form. Accordingly the genera must be 

 thus arranged. 



Scydmcenoid genera. Oxyteloid genera. 



Hamotus. Batrisus. 

 Bryaxis. 



Eupsenius. Ehexius. 



Arthmius. „ 

 Bythinus. 



B. A. 



Euplectus. 

 Faronus. 



The left-hand branch being almost typical Pselaphi, with globular thoraces, scarce- 

 ly sculptured, and leading very obviously to the Scydmami ; the right-hand branch 

 being altogether abnormal, Batrisus being the only genus tending at all to the typical 

 chain. The six-jointed abdomen and elongate form of Euplectus, proves that the 

 lower forms of this line must possess a multi-articulate abdomen, with a linear body. 

 They must therefore be sought among the Brachelytra. 



To circumscribe this large group containing Pselaphi, Scydmaeni, and Oxytelini, 

 all closely related, and to discover its higher forms (if any exist), is a work of much 

 labour, and could be undertaken only after a careful study of all the groups of Coleo- 

 ptera, and a knowledge of their larva. Since the Coleoptera have heretofore been 

 studied for the purpose of being arranged into groups rather than series, many cha- 

 racters used in defining these groups must be rejected, when we attempt to find the 

 relations of these to each other. In fact, too strict an adherence to characters indi- 

 cating states of development, has already led to the formation of two very heteroge- 

 neous tribes, the Brachelytra and Heteroraera ; the latter containing many embryonic 



of nature. But we must remember that the progress from artificial to natural ar- 

 rangement has always been slow, and that we are compelled by the limitation of our 

 own intellects, to make use of the former in order to attain the latter. Again, having 

 once discovered the true principle of definition, it is only necessary to make use of it 

 in cases of difficulty, as, for instance, in the decision of the articulate nature of Bala- 

 nus, the decomposition of the Infusoria, &c. In all ordinaiy inquiries we associate 

 with the primary idea such characters as are of less importance but more obvious, and 

 which depend on the beautiful co-relation of parts evident throughout all nature. 



