THE THORAX. 77 



peculiar (for example, the Cerambycina'), the superior plate is united to 

 the inferior without the indication of any separation, so that the parts 

 distinguished in the former can be regarded in these only as regions. 

 The prothoracic case has, besides the feet, no other limbs or peculiar 

 appendages, with the exception of two instances. In the one, we observe 

 a moveable spine on each side of the prothorax, (Acrocintts longimanus} ; 

 the second instance is found in the family of the Rhiphidoptera*, on 

 each side of the prothorax of which a contorted and twisted corneous 

 appendage is attached. All other prominences of the prothoracic case 

 are integral portions of it, and are to be considered only as processes. 

 There is a multiplicity of them and of the most distinct forms, the 

 families of the Lamellicoriiia and Cicadaria display the most remarkable. 

 The PATAGIA (patogia) of the Lepidoptera, which Kirby and Spence 

 consider as appendages of the prothorax, are not seated upon this, but 

 upon the mesothorax. 



75. 



In those orders in which the prothorax is in closer connection with 

 the mesothorax, we often find analogous parts ; but it just as often forms, 

 as well as the whole thorax, one entire piece, upon the superficies of 

 which the different parts are indicated by means of deep impressions 

 and furrows. This is the case in the Diptera and the Neuroptera ; 

 for, notwithstanding the distinctness with which the different thoracic 

 plates are marked out, for example, in the Libellulina (PL XI. No. 3, 

 f. 1 3), they are, nevertheless, h'rmly attached together, and require 

 considerable force and art to separate them. In the Hymenoptera, this 

 separation is not merely indicated, but it actually takes place. A small 

 corneous plate with two sockets, and seated quite in front of the pro- 

 thorax, represents in this order the prosternum (PL XII. No. 1 and 2, 

 B, B, B.) ; a larger plate, which has a narrow margin, and which, 

 descending perpendicularly, bows round and extends on each side 

 to the origin of the wings (the collar of Kirby), takes the place of the 

 pronolum (PL XII. No. 1 and 2, A, A.). Kirby and Spence con- 

 sider this plate as an integral portion of the second segment, and 

 confirm themselves in this view of it by its generally remaining attached 

 to the mesothoracic segment when the first pair of legs are separated 

 from the prothorax. They, consequently, think they have observed 



* Strepsiptera, Kirby. 



