350 ORDERS OF PTILOTA. 



extended, when at rest, beneath the wing-covers, without 

 being folded. 



The head of orthopterous insects is in general large, and 

 almost perpendicular in the majority, the antennae being 

 placed on its upper part, and which are of variable length and 

 structure, but often long and multi-articulate ; the eyes are 

 large and lateral ; and the ocelli, which are found in the ma- 

 jority, are placed on the forehead, sometimes widely apart : 

 the thorax, or, more strictly speaking, the pronotum, is large, 

 being in many species extended considerably backwards ; the 

 abdomen is long, generally of a conical form, and termi- 

 nated in the females of many species by an exserted appa- 

 ratus for depositing the eggs, in the shape of a sword or 

 cutlass. 



The legs of the Ortlioptera are very long, and are employed 

 in giving considerable activity to these insects, in some of 

 which these organs are simply organs fit for walking {Blatta) ; 

 in others, the fore pair of legs become instruments for seiz- 

 ing the prey {Mantis) ; whilst in the rest, the hind legs are 

 greatly increased in size, supporting strong internal muscles, 

 enabling the insect to effect leaps of great extent ; these legs 

 are also employed in some species to produce a loud chirping 

 noise by their friction against the base of the wing-covers 

 (Locusta), which noise appears to be a call of the males, by 

 which sex alone it is produced. The tarsi vary, in the num- 

 ber of the joints, from three to five ; generally speaking, the 

 body is long, and often much compressed. 



The nature of the metamorphoses of these insects is also 

 another great character by which they are distinguished from 

 the Coleoptera, the larvEc and pupa3 differing only from the 

 imago, either by entirely wanting, or having only rudiments 

 of wings. The larva and pupa of the great green grass- 

 hopper are represented in page 197. In these states the 

 insect is as active and as voracious as in that of the imao-o. 



