66 HOW ARE ANIMALS AND PLANTS DEPENDENT? 



C. Clarke 



The life history of the 

 monarch butterfly. If it is 

 possible to find some milk- 

 weed on our trip, we are 

 quite likely to find hovering 

 near it a golden brown and 

 black butterfly, the monarch 

 or milkweed butterfly. The 

 female frequents the milk- 

 weed in order to lay eggs; 

 she may be found doing this 

 at almost any time from 

 June until September. 



Egg and larva. The eggs, 

 tiny mound-shaped dots, a 

 twentieth of an inch in 

 length, are fastened singly 

 to the under side of milk- 

 weed leaves. Some instinct 

 leads this butterfly to de- 

 posit her eggs on the milk- 

 weed, for the young feed 

 upon this plant. The eggs 

 hatch out in four or five 

 days into caterpillars. Each 

 caterpillar will shed its skin 

 several times before it is full 

 grown. These caterpillars 

 possess, in addition to the 

 three pairs of true legs, four 

 pairs of prolegs which are 

 fleshy structures found on 



The female monarch butterfly lays 

 her eggs on the edge of the milkweed 

 leaf. The egg hatches and the green, 

 black, and white caterpillar feeds on 

 the milkweed. Later the caterpillar 

 fastens itself to the midrib of a leaf. 



