268 



PTILOTA : IMAGO — EXTERNAL ANATOMY. 



that it ought not to be regarded as a part of the pro-thorax. 

 MacLeay, Burmeister, and others, however, give it as a por- 

 tion of that segment, the former considering it as the 

 scutellum of the prothorax, and observing that, as these in- 

 sects are essentially fliers, this piece of the prothorax is em- 

 ployed to add strength to the mesothorax in its support of 

 the upper wings. 



The under surface of the prothorax, (T) 1, consists of a 

 central piece or prosternum (antepectus K.), which is gene- 

 rally horny, and extends in a point between the fore-legs, as 

 is especially the case in the spring beetles {Elateridce), and 

 two lateral pieces, which are very distinct in the predaceous 

 beetles. These are the epimera and episterna of Audouin, 

 and sometimes the ora of Kirby and Spence. In addition to 

 the various horns or protuberances which arise from the pro- 

 thorax, but which are only continuations of the external 

 crust, there are several distinct appendages to be noticed. 

 Of these, the legs are the most important, the basal piece of 

 which often appears to form a constituent part of the pro- 

 sternum, but is, nevertheless, moveable ; the first pair of 

 spiracles are also parts of the prothorax. 



Vies. 124, ilorsal view of the thorax of a wasp; 125, lateral view of ditto, lettered as : 

 figs. 118—123. 



