1W'¥J'^-^ 



they hatch to produce minute larvae. The larvae feed on the leaves of the 

 plant, molting several times as they increase in size during the 2 or 3 weeks 

 of the larval period. Mature larvae are light-green caterpillars, conspicuously 

 banded with black and yellow stripes, and with pairs of antenna-like projec- 

 tions toward each end. The molt marking the end of the larval period pro- 

 duces the so-called chrysalis, or pupa, in which such distinctive adult features 

 as wings and antennae are recognizable. The adult emerges after 10 or 15 

 days, inflates its wings, and appears as the familiar flying form. In autumn 

 the adults are killed by cold, or they migrate southward in great swarms to 

 pass the winter in subtropical regions, returning to the north in spring. 

 Other butterflies have different seasonal relationships, some passing the 

 northern winter in the pupal stage, others as eggs that hatch in earlv spring. 

 Moths, of which there are very many species, are usually nocturnal in their 

 activities, whereas butterflies are typically active during the daylight hours. 

 Moths have feathery antennae and hold their wings horizontally at rest; 

 butterflies have slender, clubbed antennae and hold their wings vertically. 

 Again, the pupal stage of the butterfly is typically a naked chrysalis attached 

 to some object by a single thread; the pupae of most moths are surrounded by 

 cocoons of silk, spun during the last larval stage. At the close of the pupal 

 period, the pupal skin is molted within the cocoon, and the adult forces its 



467 



