60 POPULAR ENTOMOLOGY. 



the base of the under-wings, which, passing through a hook 

 on the under side of the anterior pair, maintains them in 

 their horizontal or inclined position. Having thus separated 

 the Moth from the Butterfly, we must endeavour to divide 

 the former from the Hawk-Moth. The most characteristic 

 mark of the latter is to be found in the different form of the 

 antennae, which has been described above ; the wings too 

 are longer, narrower, and of a firmer consistence than those 

 of the true Moth, being also of smaller size, when compared 

 to the body ; by their rapid vibration, the insect is poised in 

 the air like a Hawk (hence its name), and as many of the 

 species, when thus hovering, make a slight humming sound, 

 and in this respect, as well as in the rapidity of their move- 

 ments, bear some resemblance to humming-birds, they are 

 known under the mixed name of Humming-bird Hawk-M oths. 

 There are also some differences observable in the Cater- 

 pillars of the three divisions. Those of Butterflies have 

 usually sixteen legs, six of which are placed on the anterior 

 part of the body, which represents the thorax of the future 

 insect, and these legs are divided into segments corresponding 

 to the parts which compose the leg of the Butterfly ; the 

 others, called prolegs, and attached to the hinder part of 

 the body, are soft and fleshy, seeming to be principally used 



