156 THE ORTHOPTERA. 



changing their skins_, becoming more and more like 

 the perfect insects after each moult^ until in their 

 last preparatory dress they exhibit the marks of their 

 folded wings upon the integuments of the thoracic 

 segments; and on casting off their last temporary 

 coatj the wings soon acquire their proper dimensions. 

 Through the whole of this period of growth the young 

 animals are active and voracious, never passing into 

 that quiescent condition, which even the most agile and 

 predaceous of the beetles are condemned to undergo. 

 Many of these creatures, especially the females, never 

 acquire wings, even in their mature state, and the 

 larvse of these are in consequence scarcely distinguish- 

 able from the perfect insects, except from their small 

 size ; a circumstance which has added not a little to 

 the difficulty of studying them. 



The nature of the wings, when present, affords one 

 of the principal structural differences by which the 

 Orthoptera are distinguished from Beetles. As in 

 the latter, the anterior wings are of little or no use in 

 flight, serving chiefly as a covering for the large pos- 

 terior pail', but instead of being simple horny sheaths, 

 as in the generality of beetles, they are of a flexible 

 leathery or membranous texture, and their substance 

 is traversed in various directions by numerous veins. 

 Moreover, instead of meeting down the back by a 

 straight suture, they usually lap over each other more 

 or less. The structure of the hinder wings is equally 

 if not more characteristic. They are of large size, 

 and nearly semicircular, and their principal veins 

 radiate like the sticks of a fan from the centre to the 

 circumference, so that the wings when folded lie per- 

 fectly straight down the back of the insect, without 

 any of the transverse folding observable in the wings 



