THE THORAX. 'Ji) 



(PI. XII. No. 1 and 2, d, d ; see 77)- The first spiracle is constantly 

 the property of the prothorax throughout all the orders which have this 

 part free, and in a very flexible articulation with the second ; conse- 

 quently, in all the remaining orders, the first spiracle of the thorax 

 must necessarily belong to its first segment, and not, as would be the 

 case were the collar a portion of the mesothorax, to the second thoracic 

 segment. 



Srdly. We may even adopt, as proofs in our favour, the reasons cited 

 by Kirby and Spence, in opposition to their own views. In the first 

 place, they say the collar lies directly over the prosternum (Chlorion), 

 and then moves freely with it (Pompilus, Chrysis), when the 

 collar has no prophragma (see lower down) ; but which is found 

 upon the dorsal piece lying behind it. Kirby and Spence have not 

 refuted all these reasons, but have considered them as rendered ineffec- 

 tive by their contrary reasons, which we have entirely refuted. It 

 clearly appears to us, therefore, that the term COLLAR will, in future, 

 be useless, and instead of it, this part must be called by its more 

 appropriate name of pronotum. 



In the order of the Lepidoptera, this pronotum approaches to the 

 shape of a collar, for in them it leans against the second segment, in 

 the form of a thin plate, and thus forms its commencement (PI. XII. 

 No. 1, f. 1, ). Besides which, it is here called collare by the describers 

 of Lepidoptera, particularly wherever it is covered with differently 

 coloured hair, or small scales. But even here it is the true represen- 

 tative of the pronotum. 



76. 



The intermediate ring of the thorax, the MESOTHORAX consists, in 

 its most developed state, of seven pieces, the three pairs of which are 

 so closely united, that each appears to form but one piece ; thence, 

 consequently, we have four chief pieces, which we distinguish as MESO- 

 NOTUM, MESOSTERNUM, and the SCAPULA. 



The MESONOTUM (PI. IX. &c. c, c, c. Kirby and Spence's dorso- 

 lum and scutellum), forms superiorly the corneous covering of the 

 mesotliorax. It is generally of a quadrate shape ; it is convex on the 

 exterior and concave within, bent down laterally, and is here, chiefly* 

 in direct union with the remaining corneous plates. It is divided into 

 two parts, which are never distinctly separated, but merely indicated 

 upon the superficices. The anterior piece or true back (dorsolum of 



