432 NATURE STUDY. 



often " straddle " the leaf. Why ? How they move their 

 head. The motion from side to side of their jaws. 

 Why so different from ours ? 



With a magnifying glass, three small black eyes can be 

 seen on each side of the head, near the mouth. 



Spinning. After a few hours the inside of the can be- 

 comes covered with silky threads like spider's web. With 



Fig. 43. Danais Caterpillar. 



magnifying glass, or a very sharp eye, the silk can be seen 

 to come from a little projection below the mouth. Watch 

 the head move from side to side in laying these threads 

 on the glass, and notice how the caterpillar uses them in 

 crawling or climbing. 



Life History. Chrysalis and Adult. 



Tell about the egg, and its development into a cater- 

 pillar. 



The eggs may possibly be obtained if the butterfly is con- 

 fined in a cage with the milkweed plant. If patiently 

 watched in 1 the fields, the butterflies can often be seen to 

 lay their eggs on the milkweed leaves. 



Perhaps the children may discover the caterpillar in the 

 act of moulting or shedding his skin. He eats so much and 

 grows so fast that his skin soon becomes too tight for him. 

 It splits along the back, and is gradually pushed off. Sev- 

 eral times this is done. 



In time the caterpillar will become restless, arid finally 



