INTROD UCTION. 



The antennae, or feelers, vary greatly and often serve as a means of distinguishing between 

 different groups. They are composed of a number of separate joints (from thirty to over an 

 hundred), the first of which is called the basal joint and is usually stouter and longer than the 

 others. This joint varies much in length and form even in the same species, and in some, as 

 in the Bombyces, helps to distinguish between the sexes. The antennae are called clubbed, 

 when they are gradually thickened to the extremity, as in Papilio ; capitate, when the 

 thickening takes place abruptly, as in many butterflies; filiform, or thread-like, when they 

 are of uniform thickness throughout their length; setiform, or bristle-shaped, when they taper 

 towards the extremity; fusiform, or spindle-shaped, when they are thicker in the middle than 

 at the two ends, as in the Sphinges; moniliform, if composed of a number of short rounded 

 joints like a string of beads. The antennse may be covered with fine hairs. If the hairs 

 are regular and arranged in parallel columns they are said to be ciliated. The hairs may 

 be uniformly thick or arranged in pairs or in tufts. 



The compound eyes occupy nearly the whole of the side of the head. They are spherical, 

 and are formed of a number of small facets, each of which may be regarded as a small eye: 



