22 



ELEMENTARY STUDIES IN INSECT LIFE 



come moist; then the case gives way along the back, 

 owing to the muscular contractions within, opening a 

 way for the appearance of the black head and legs. 

 Slowly and cautiously the legs become effective, and in a 

 moment's time the smooth inner walls have permitted 

 the escape of the delicate creature ; cautiously it climbs 

 over the old shell to the supporting twig, there to await 

 the sun's strengthening action upon its four wrinkled, 

 folded and limp wings. The body strengthens, the 

 wings expand, the colors stand out, the life and courage 

 increase, and it takes its initial flight. (Frontispiece.) 



" Butterfly, good-by to your shell, 

 And bright wings speed you well." 



This butterfly, in the form in 

 which we have thus far studied it, 

 had, during its caterpillar stage, 

 a mouth with jaw r s fitted for mas- 

 ticating vegetable food. During 

 this eating period sufficient nour- 

 ishment was stored for pupation. 

 Now this same individual, in adult 

 form, a butterfly, no longer has the 

 means nor the power for biting off 

 bits of plant leaves. The butterfly, 

 then, must obtain its food in an- 

 other form. This it finds in the 

 nectar of flowers. To enable it to 

 reach the nectaries within the blos- 

 som, the butterfly is equipped with 

 a long sucking-tube or proboscis. You will not readily 

 perceive this when you first capture the butterfly, since, 



FIG. 23. Empty pupa-case 

 of black swallowtail, show- 

 Ing characteristic opening 

 through which butterfly 

 emerged. 



