CONSIDERATIONS. 479 



prt'tpcmlitre and ipaulieres of the mesothorax. The first is 

 termed preaxillaire ; the others j)re7niere, seconde, troisieme, 

 and quatrieme axillaire. 



The mesothorax, and metatJiorax, of the other Coleop- 

 tera, offer but httle different from that of the Melolonthce ; 

 but there are modifications which may be pointed out as 

 serving to throw hght on the subject of classification and com- 

 parative anatomy. In Forficula, the thorax^^ is much nearer 

 in form to that of Lepisma than to that of Coleoptera or 

 Orthoptera, differing most, however, from that of the last 

 order. In fact, it is precisely intermediate between that of 

 Lepisma and Stapliylinus. In Staphylinus olens, the seven 

 pieces which form the clypeus are separated by very distinct 

 sutures. In the Apterous Coleoptera the absence of wings 

 causes considerable difference in the form of the tliorax. The 

 membranous space in which the wings are inserted is wanting, 

 or, rather, is filled by the greater development of the neigh- 

 bouring parts ; the tergiim, which is curved inwards where the 

 wings exist to serve as an attachment for the muscles, now 

 regains its primitive form, as the upper portion of the first 

 abdominal segment. Lastly, the upper surface of the meta- 

 thorax becomes membranous ; and the different parts of which 

 it is composed no longer present the different apophyses which 

 were necessary in the winged species. 



The abdomen, bearing no external member which can 

 influence its structure, its segments take the most simple 

 structure possible, — each, with the exception of the first, being 

 merely composed of two principal parts, one superior, the other 

 inferior, united by a membranous space, becoming less and less 

 wide towards the extremity. This allows the abdomen to 

 dilate, or contract according to the state of the viscera. 



Edward Doubleday. 



■• In this instance and another, seven lines below, our correspondent has 

 applied this term to the meso- and metathorax, united ; in all other instances he 

 has made his names conform with those of Mr. Newman, at p. 394. — Ed. 



(To heconliimed.) 



