feC»VVVAX\V\\W\\\\\\\\\\\< 



WINGED INSECTS. 299 



full complement of segments, with their accom- 

 panying legs. The Julus terrestris, for example, 

 (Fig. 143) has, at its entrance 

 into the world, only eight 

 segments and six feet ; but 

 acquires in the course of its 

 developement, fifty segments and about two 

 hundred feet. The anterior legs are directed 

 obliquely forwards, and the rest more or less 

 backwards. The mandibles have the form of 

 small feet ; as we have seen is frequently the 

 case in crustaceous animals. 



§ 2. Insecta alata. 



Our attention is now to be directed to the more 

 highly developed Insects, which have been 

 formed with a view to progression through the 

 air. On these, which compose the most exten- 

 sive class of the whole animal kingdom, Nature 

 has lavished her choicest gifts of animal powers, 

 as far as they are compatible with the diminu- 

 tive scale to which she has restricted herself in 

 their formation. The model she has chosen for 

 their construction is that which combines the 

 greatest security against injurious impressions 

 from without, with the most extensive powers of 

 locomotion ; and which also admits of the fullest 



