15 



terior portion, which bears the third pair of legs and the under wings (wings 

 proper), and to which the abdomen is joined, is the metatliorax. 



The different surfaces of these divisions are distinguished by separate 

 names : thus, the dorsal portion of the prothorax is the pronotum (Fig. 2, pr), 

 and the ventral portion the prosternum ; the dorsal portion of the mesothorax 

 is the mesonotum, and is usually covered by the pronotum ; the ventral poi-- 

 tion is the viesosternum ; the dorsal poi'tion of the metathorax is the metano- 

 tiim ; the ventral surface the metasternuni. The whole of the under surface 

 of the thorax taken together is the sternum (PL, Fig. 8, shows the sternum 

 of Acridium americamun). 



The most important of these divisions, in describing genera and species, 

 is the pronotum ; this is the shield which covers the front part of the body 

 immediately behind the head (Fig. 2, ^^r), reaching down the sides nearly or 

 quite to the insertion of the front legs ; it usually extends back on the dorsum 

 of the thorax, so as to cover the base of the elytra (wood-cut, Fig. 2, pr ; see 

 also PL, Figs. 1, 2, 3, and 5); but in the sub-family Tettigince it extends 

 back over the abdomen to its extremity (see PL, Fig. 14), Its surface is 

 considered with reference to three planes — the upper surflxce (dorsu?n), and 

 the two sides ; but there are wide variations from this typical form. When 

 these areas are clearly distinguishalile (as in Pyrgomorpha, PL, Fig. 10 ; 

 Oxycoryphus, PL, Fig. 6 ; Eomxilea, PL, Fig. 2 ; Bracliypeplms^ PL, Fig. 4, 

 and many other genera) there is a raised line, sharp angle, or obtuse 

 ridge running along each margin of the dorsum, where it connects with the 

 side (this is represented in PL, Fig. 4, Ijy tlie double line, which, starting 

 immediately back of the eye, runs to the upper .margin of the scale-like elytra); 

 these are called the lateral carincB. In most species of the family there is a 

 raised line or keel along the middle of the i;)ronotLim called the median carina 

 (wood-cut, Fig. 1, inc) ; this is sometimes bnt an indistinct line (see PL, 

 Figs. 9, 10); in other species it is quite cfistinct ; in some slightly elevated, 

 when it is said to be sub-cristate ; and sometimes (see PL, Fig. 1) it is 

 quite elevated, when it is called cristate. The term carina is sometimes, 

 though with doubtful propriety, applied to the obtusely-rounded angle formed 

 by the deflection of the sides of the jironotum from the dorsum (as in Calop- 

 tenus, PL, Fig. 5, and even in Fezotettix, PL, Fig. 15, where the prono- 

 tum is almost cylindrical). I have, therefore, in some cases introduced the 

 term huinrrus or humeral angle to represent this part when it cannot properly 



