Expi,ANATiON OF Pirate 19. 



This plate illustrates the development of the color pattern upon the'elytra 

 of several species of Leptinotarsa. 



Figs. I to 6, Z. undecimlineata* 



Figs. 7 to 12, Z. dileda. 



Figs. 13 to 18, L. zetterstedti. 



Figs. 19 to 24, L. rubiginosa. 



Figs. 25 to 30, L. violescens. 



I 



