STUDIES OF INHP]RITANCE AND EVOLUTION 

 IN ORTHOPTERA. IIP. 



By ROBERT K. NABOURS. 



In the first instalment of this study, Journal of Genetics, Vol. ill. 

 pp. 141—170, the crossing of the hybrid ^ Ci^ with a hybrid % BI, 

 Table III (b), was reported which produced the approximate normal 

 exjjeetation of BC 12, BE 11, CI 7, and EI 10, and an unexpected 

 individual, a male, showing the combination of the three patterns B, E, 

 and / {BE I). This aberrant individual was discovered at an early age 

 and its pattern was clearly marked at all times, and especially well soon 

 after moulting when patterns are always at their best. It became adult, 

 but was lost before any matings were made. It was suggested in the 

 report that perhaps the female had produced an abnormal gamete con- 

 taining the factors for both B and /, and that this was fertilized by a 

 normal gamete from the male containing the factor for E'^. 



Explanations of the causes of this phenomenon have been proposed 

 by Dexter {'14), and Bridges ('16), and comments have been made upon 

 it by Castle (14), and Morgan ('14). 



No other such individual was observed in any of the Paratettvr 

 cultures until the summer of 1915, when a form combining the patterns 

 of B, S, and a modified / appeared among the progeny of a mating 

 (472) of IS X BS. This aberrant BIS individual, a male, was mated to 

 three females, BG (mating 486), BS (mating 488), and BB (mating 

 482), respectively. Reference to the accompanying tables and to the 

 tables in the second instalment will indicate the ancestry of the parents 

 in this mating (472) and also show the breeding behaviour of the 

 progeny and relatives. (See Plate II in second instalment.) 



1 Contributiou from the Zoological Laboratory of tlie Kansas State Agricultural College 

 and Experiment Station, No. 11. 



The first instalment appeared in the Journal of Genetics, Vol. in., and the second in 

 Ibid. Vol. vii. pp. 1 — 46. 



- The other apparent exceptions referred to in tlie first instalment were those cases 

 involving the factor 9, which are considered in the second paper. 



