BLENDING CHARACTERS 187 



impracticable. 1 Other experiments with Lepidoptera have 

 shown segregation. 2 The results he obtained from breeding 

 Lepidoptera led Mr. A. Bacot to express the opinion that the 

 characters blend when geographically separated races are 

 crossed. In order to obtain segregation of the parental forms 

 from hybrids, aberrations occurring in a race occupying the 

 same geographical area must be crossed ; and he believes 

 that all recorded instances of Mendelian inheritance among 

 Lepidoptera are of the latter class. 3 The same opinion is 

 repeated in the joint paper with Mr. Prout describing the 

 experiments referred to above. 



Now this conclusion exactly coincides with the hypo- 

 thesis that individual characters are transmissible in an 

 alternative manner, while racial characters tend to blend. 

 Various theoretical interpretations of the blending of char- 

 acters have been put forward in order to make them com- 

 patible with the obvious Mendelian results. It has been 

 stated, for instance, that when an intermediate colour be- 

 tween the parents appears in the offspring, the two colours 

 really remain distinct, and are present as a very fine mosaic. 

 Many such characters have, however, shown no tendency 

 to segregate in the offspring, and this interpretation seems 

 therefore too far fetched to be probable. 



With regard to the classification of inheritance as 

 blended, exclusive, and particulate, it would seem that 

 the blended characters are generally racial. In cases of 

 exclusive inheritance, some may be impure dominants, and 

 it may be the same with regard to particulate inheritance. 



It seems quite probable that the so-called aberrations 

 in the breeding experiments with Lepidoptera referred to 

 above, correspond to what have been very generally called 



1 Prout, L. B., and Bacot, A., " On the Cross-breeding of the moth Acidalia 

 virgularia," Proc. Roy. Soc., B. vol. Ixxxi., 1909. 



2 Bacot, A., Entomologist's Record, xiii. pp. 114-17 and 142-44. 



3 Similar results have been obtained by Prout and Bacot with Triphcena 

 conies and its dark aberration, Entomologist's Record, xv. and xvi. ; Xanthorhoe 

 ferrugata and its black aberration, Trans. Entomological Society, London, 1906, 

 and Proc., 1907. 



