Beautiful Butterflies. 41 



are three-jointed, and in shape like this. In this cut, 

 the letter a indicates the organ I have been describing ; 

 and I the antenna, plural antennce. The term I have 



used before in describing the insect in its larva state ; 

 but I did not then speak of its derivation. The Latin 

 word antenna means the sail-yard, as it is called, of a 

 ship, that is, the piece which crosses the mast, and to 

 which the canvas is affixed ; these horns of the insect, 

 in some cases sticking out in nearly opposite directions 

 to each other, suggested the idea of the cross-pieces on 

 a mast, and so the same Latin name was applied to 

 them. They are generally of considerable length, and 

 consist of a great number of joints, usually increasing 

 in thickness towards the extremity, where they form a 

 kind of knob; this formation you must often have 

 noticed ; it is peculiar to the Diurnal Lepidoptera, and 

 by its variations of shape affords an obvious distinction 



