316 



The Mechanism of Evolution in Leptinotabsa 



56 Al 



818 Males. Total 1546. 728 Females. 

 Fio. 132. — First census at San Marcos in 1908, showing the pronotal pattern. 



I»~ 



.4B 



«-4p 



1073 Males. Total 2263. 



12 

 1190 Females. 



Fio. 133. — Second census at San Marcos In 1908, showine sudden change In 

 the population as a whole and sudden appearance of Isolated groups In biotrpes 

 6, 8, 12, and 10. 



51 ti ^9 31 55 26 25 31 11 41 33 



1230 Males. Total 2531. 1301 Females. 



Fio. 134. — First census at San Marcos In 1909, showing an Increased array 

 In pattern conditions with total elimination of isolated groups present In the popu- 

 lation in previous censuses. 



