152 



PHYSIOLOGY OF INSECTS. 



inferior margin ; posteriorly it borders on the hinder coxa ; 

 above it partly covers the membranous band of the first 

 segment of the abdomen." 



The upper surface of a beetle is extremely simple : 

 first we see the head, then the pronotum, usually de- 

 scribed as the prothorax ; behind this are the proalce, 

 fore wings or elytra, quietly folded on the back, and 

 completely covering the hind wings; between the elytra, 

 at their base and adjoining the prothorax, we see a trian- 

 gular plate, which is the mesoscutellum or scutellum of the 

 mesothorax ; this is invariably described as the scutellum 

 of beetles : the pin in the vignette below is pointing to the 

 unusually large scutellum of Macraspis. 



