XVI 



LIFE-HISTORIES 



325 



second birth, and enters upon a phase of life which is pre- 

 occupied with reproduction and only secondarily (some- 



FIG. 109. DIAGRAM OF THE LIFE-HISTORY OF A SMALL WHITE 



BUTTERFLY (Pieris raptc). 



Im, the imago, with knobbed antennse and two pairs of scale-covered 

 wings loosely linked together. 



E, the egg very much enlarged. A small circle to the right is in pro- 

 portion to the butterfly. The shell of the egg is made of chitin and 

 beautifully sculptured. The head end of the unhatched caterpillar is 

 protruding. 



C, the caterpillar. It has a hard head and thirteen segments. The 

 first three behind the head bear jointed clawed legs corresponding to 

 the legs of the adult. Posteriorly there are five pairs of unjointed, un- 

 clawed pro-legs (see fig. 76). 



PI, the early stage of the quiescent pupa. PZ, a later stage from which 

 the imago is beginning to emerge. 



There are thus four chapters in the life-history : the egg and embryo ; 

 the larva ; the pupa ; and the imago. 



times not at all) with nutrition. The active winged butter- 

 fly, to whom " love " means much and " hunger " little. 



