i] PARTIIKXOGENESIS AND CROSSIXG-OYER 



141 



processes, or both, involved in the parthenogenesis must 

 await further investigation. 



In nature, individuals of the pattern AA, of a mottled 

 gray ground color, in striking contrast with, and much 

 less conspicuous than, the rest, exceed in numbers 

 all the others combined. This situation has been ac- 

 counted for in the past by the assumption that the bril- 

 liant patterns rendered the individuals possessing them 

 so conspicuous that they more readily fell prey to en- 

 emies, while the inconspicuous and protected AA indi- 

 viduals were largely unmolested. Now, since it has been 

 demonstrated that crossing-over among the forms of con- 

 spicuous patterns produces the A gametes as well, the 

 cause of the preponderance of AA patterns in nature 

 may, in part at least, call for an entirely different ex- 

 planation. AA may be the primitive form and the others 

 have originntc^l from it, by mutation or in some other 

 way. The form A A seems to coi-respi^iid to llio so-called 

 "normal" oi- wil. I tvi.e," ilu.udi all the others have also 

 been found exclusively in nature, none (in Jpofcflir) 

 having so far originated in the hiboratory. 



Conclusions 



1. Through complete isolation of females from males 

 of any kind, in some cases for as many as three u'euera- 

 tions, and, in addition, by genetic behavior, it has been 

 demonstrated that these forms of ApnirHi,- are ,u> iio- 

 genetically, except rarely parthenogenetic ( t\ choJ)arthe 

 nogenetic). 



2. Segregation is demonstrated as occurring in hetero- 

 zygous individuals reproducing l)y parthenogenesis, as 

 well, and apparentlv to the same extent. in those 

 females reproducing bisexnallx'. 



erozygous indi vidnals reprodncinii: bv pa rtlnaiogenesis, 

 as w,qi, and a])par.'ntlv to the same .xtent. as i,i those 

 females reprodncing bisexually. 



4. C*rossing-over occurs in the male, as well, but ap- 

 parently not to the same extent, as in the female. 



