HAED PAETS OF THE GRASSHOPPER. 249 



the lower ends of the metathoracic epistema (c") , separ- 

 ating the fossae of the second legs from those of the third, 

 and sending prolongations backwards to form the inner 

 margins of the latter 



(iii.) Make a drawing of the ventral view of the thorax, 

 showing these points. 



(iv.) In a side view of a thorax, from which the prono- 

 tum, wings and legs have been removed, the space above 

 the leg fossa is occupied by four rectangular pieces, 

 which slope obliquely upwards and forwards. The ante- 

 rior margin of each of these is marked by a dark stripe 

 or band of pigments, and the posterior margin by a light 

 stripe. > 



1. The first or most anterior piece is the mesothoracic 

 episternum. Its lower margin is prolonged downwards 

 and backwards, and forms the anterior and lower boundary 

 of the fossa of the second leg. 



2. The second piece is the mesothoracic epimeron. Its 

 lower end forms the upper and posterior margin of the 

 leg fossa. 



3. The third piece is the metathoracic episternum. 



4. The fourth is the metathoracic epimeron. 



5. Between the mesothoracic epimeron and metathoracic 

 episternum, just above the mesothoracic leg-fossa, is a 

 small oval aperture provided with a pair of lii>like chitin- 

 ous valves. This is the respiratory aperture or spiracle 

 of the metathoracic sesrment. 



6. Along the upper margins of the epistema and epi- 

 mera are a few small irregular pieces, to which the wings 

 are articulated. 



(v.) Make a drawing of the side view of the thorax, 

 showing these points. 



(vi.) The dorsal surface of the mesothorax and metar 



