LEGS. 31 



and at the point of junction with the head the base ia 

 spread out (as shown at fig. 15), forming what engineers 

 call a " flange," to afford sufficient support for the long 

 column above. 



The legs are the last portions of the butterfly frame- 

 work that require especial notice, on account of a 

 peculiar variation they are subject to in different family 

 groups. 



It may be laid down as an axiom, that all true in- 

 sects have six legs, in one shape or another ; and butter ■ 

 flies, being insects, are obedient to the same universai 

 rule, and duly grow their half-dozen legs; but in certain 

 tribes the front pair, for no apparent reason, are so short 

 and imperfect as to be totally useless for walking pur- 

 poses, though they may possibly be used as hands for 

 polishing up the proboscis, &c. So the butterfly in 

 this case ajipears, to a hasty observer, to have only four 

 legs. 



This peculiarity is a constant feature in several natural 

 groups of butterflies, and therefore, in conjunction with 

 other marks, such as the veining of the wings and the 

 shape of the antennas, its presence or absence is a most 

 useful mark of distinction, in classifying or searching 

 out the name and systematic place of a butterfly. 



