108 ELEMENTARY LESSONS ON INSECTS 



The antennae are generally large and prominent. They 

 are knobbed or clubbed on the end in butterflies, and var- 

 iously formed in moths. The eyes are large and the ocelli 

 are small and often (the median one always) absent. The 

 wings are usually flat and broad, unfolded, but held when 

 at rest in a great variety of positions. In most butterflies 

 they are closed together and held vertically above the back. 

 A venational characteristic of the order is seen in the fading 

 out of the base of the median vein within the confines of an 

 area known as the discal cell. Wings are wanting sometimes, 

 as in the female moths of the cankerworm. 



The legs are generally slender; the tibiae often bear spurs, 

 as in the caddisflies. In one large family of butterflies (Nym- 

 phalidae, the family of the common fritillaries) the fore legs 

 are vestigial and these butterflies, therefore, are quadrupeds. 



The young, or larvae, of Lepidoptera are called cater- 

 pillars. They are more or less cylindric and wormlike and 

 have biting mouthparts. They spin silken thread. That is 

 one of their most characteristic habits. They are mostly 

 herbivorous and consume every sort of vegetable substance. 

 Collectively they are the greatest consumers of herbage on 

 the earth. Among them are very many of our most impor- 

 tant economic insects. 



The head of the larva is small and is encased in a horny 

 capsule, with small eyes and antennae at its sides. The 

 mouthparts are not like those of the adult, but are of the 

 ordinary biting type, only with reduced palpi. Labrum 

 and labium above and below, with two pairs of jaws swing- 



