CAIJUAGK BUTTERFLY 



137 



Place some larvae in a cyanide bottle. Study and draw 

 a specimen. Can you find the six single eyes (ocelli) on 

 the side of the head ? Note the small feelers (antennce), and 

 the strong teeth (mandibles). How many pairs of jointed 

 legs has the thorax ? How many imsegmented legs (-prolegtty 

 on the abdomen? Note the number of segments 011 the 

 abdomen, and locate, if possible, all the spiracles. 



Pupa. After a larva is 

 full-grown it ceases to eat 

 and becomes restless, leav- 

 ing the cabbage and crawl- 

 ing about. When these 

 symptoms are seen, keep 

 a larva under a glass for 

 observation. Note that it 

 spins a mat of silk into 

 which the claws of the 

 last pair of prolegs are 

 fastened, and a girdle of 

 silk over the middle of 

 its back. After it is thus 

 securely fastened it draws 

 its head down. When it 

 has remained in this posi- 

 tion for some time, the 

 skin splits over the head 



FIG. 73. Insect case to show biology of cab- 

 bage butterfly 



and thorax, and we find a chrysalis in place of the green larva. 

 Draw the pupa as it is fastened by its girdle. Search for 

 pupae and make a list of places where they are found. Save 

 as many as possible in order to see the butterflies emerge. 



Adult or imago. The rapid distribution of cabbage butterflies 

 is due to their flight across the country from garden to garden, 

 and to the conveyance of the chrysalis on carriages and trains. 

 Follow the butterfly for fifteen minutes and keep a record of 



