Analysis of Heterogeneity in the Population 277 



The season of 1909 was the last in which this series was followed methodically 

 in this location, and completed a series of 12 censuses of 12 successive genera- 

 tions at one location, in a population of fairly restricted character and habitat. 

 The first census of this season did not show any conditions greatly different from 

 those found in pj-evious determinations. The season opened with rains at 

 unusually early dates, so that there was much reproductive activity in late May, 





n-^mx oft ^'"" v^Sp ^%i i^'-' 



19 ..j^ ^ , :^-- 31 



41 sm.^- m^- 9 



42 j^ 5^ 4j ^^ ^ 



51 j^ ^ 77 ^^ Xj^ 1^2. 45 



44 «. ^ ---19 ^g....^.,_..:..^^^. 101 



,61— -•■ ^ -^ ^21 ^mi^- m-- 1« 



** ^^ "^ T^'t"/^^^ 22 



, ** ■**'^^ 3^ / / ^^^*'\ -^^ -31 



/ \ / / myy^^^^-- ^ 



/ \ / / / \ \ \"%^: — « 



6 19 18 14 12 15 8"^ 



799 Males. Total 1523. 724 Females. 



Fio. 64. — Census of first annual generation at Chapultepec colony In 1909, 

 showing the array in the pronotal pattern. 



9- iA' 



8- 

 9- 



14- - ^ _ 



4- ^. '^ 31 -^ m^ 



8 - - ^ '^^'^ ^ 

 19 -^ X,,,_ 1** *^ ^^ 19 



^"" 31 43 ^ ^ g^ 



31 ,ai? -av 61 



IS - - - ife!* *6. - 116 



«*»«»*« «^ 145 



^Isf^ 'I2 / / Jf* ^?*^ 51 



41 ^ Vjft¥--^^ 45 



43 ^; ^ _;:^ 41 



8 ^. -- - tj^ W- — 92 



''m >m ^ <^-^- 161 



/ .' .' ^ ' / / ^ ^ ' 



9 4 15 31 7 9 14 1 4 22 



632 Males. Total 1401. 769 Females. 



Fio. 65. — Census of second annual generation at Chapultepec colony in 1909, 

 showing the array of the pronotal pattern. 



with widely ranging conditions in the humidity, rainfall, and desiccation. The 

 population that started its development in this period showed that the males 

 were much reduced in all biotype lines, with the exception of 1, 2, 3, and 4, the 

 absence of 12, and portions of 11, 10, and 9, while the extreme of 10 and part of 

 11 were present as isolated groups. The females, however, showed nearly all of 

 the lines present to their full extent, and no isolated groups, so that the condi- 

 tions in the two sexes in the population were quite different. 



