PHYLUM ARTHROPODA 



351 



larvae of the Lepidoptera are called caterpillars, and are in 

 many cases extremely injurious to vegetation. 



Over seven thousand species of Lepidoptera have been 

 described as inhabitants of this country. These may be sepa- 

 rated for convenience into two suborders, (1) the Rhopalocera 

 or butterflies and skippers, and (2) the Heterocera or moths. 



Suborder i. Rhopalocera (Butterflies and Skippers). 

 — The butterflies and skippers may be distinguished from, the 



Fig. 283. — Order Lepidoptera. Monarch butterfly, Anosia plexippus. 



(After Riley.) 



moths by the knoblike swelling near the end of the antennae. 

 The skippers usually possess in addition to this knob a ter- 

 minal recurved point. Moths do not possess knobbed antennas. 

 The members of the two suborders differ also in habits, since the 

 butterflies are active during the day, whereas the moths usually 

 fly at night or twilight. 



Most of the skippers belong to the family Hesperid^e. 

 They are generally small and comparatively dull-colored Rho- 

 palocera that " skip " about close to the ground from one plant 

 to another, like a wounded butterfly. 



The beautiful swallowtail butterflies belong to the family 

 Papilionid^e. They are characterized by one to three " tails " 

 projecting backward from their hind wings. The tiger swallow- 



