280 



ORTHOPTERA 



CHAP. 



eyes, laterally somewhat compressed body, long hind legs with 

 femur directed upwards and backwards, the knee-joint forming 

 an acute angle, the organs of flight pressed to the sides of the 

 body, our common grasshoppers represent the Acridiidae quite as 

 truly as do the gigantic exotic forms, some of which measure 

 9 or 10 inches across the expanded wings. 



The large head is immersed behind in the thorax ; the front 

 is deflexed, or even inflexed, so as to be placed in a plane at an 

 acute angle with that of the vertex (Fig. 165); the compound 

 eyes are placed at the sides of the head and rather widely 

 separated ; in front there are three small ocelli. Two of these 



are placed one on each side close to 

 the eye between the eye and the base 

 of the antenna ; the third ocellus 

 being in the middle just in front of 

 the insertion of the antennae, be- 

 tween the edges of the margined 

 space that usually runs down the 

 middle of the front. The positions 

 of these ocelli and the shape of the 

 front and upper parts of the head 

 are of importance in the classification 

 of the family ; the ocelli vary much 

 Fig. 166. Front of head of PoWAe^ts in their development, being in some 

 sp. Transvaal. species beautifully clear and promi- 



nent (Fig. 166), while in others they are small, not easily detected, 

 apparently functionally imperfect. The antennae are never very 

 long, are sometimes compressed and pendent from the front of the 

 head. The parts of the mouth are very large. The prothorax is 

 much arched ; it is often carinate or crested along the middle of 

 the notum ; this part is frequently prolonged backwards, forming a 

 sort of hood over the base of the wings ; the surface may be 

 rugged or warty, forming in some species inexplicable structures ; 

 the legs are widely separated, all of them being placed at the 

 sides of the body; the edge of the pronotum is distinct and 

 situate close to the base of the leg ; the prosternum frequently 

 bears a large projection extending directly downwards between 

 the front legs. The mesothorax is short, its chief sternal piece 

 is very broad, the middle legs being very widely separated. The 

 metathorax is larger ; its sternal plate usually exhibits behind a 



