No. 579] SHORTER ARTICLES AND DISCUSSION 



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character. Female U must have had the same constitution, but 

 had probably mated with both kinds of males. 



The crucial test between the two views was furnished by 

 mating a dark female from culture T to a light male from J. 

 The result was 25 dark females and 26 dark males. This is the 

 expectation if the character is sex-linked ; but if light is recessive 

 in the females and dominant in the males, the mating should 

 have given only dark females and light males. The light char- 

 acter is, therefore, sex-linked and recessive. 



A further test was made by mating heterozygous females (one 

 from Q and one from V) by their light brothers. Table II 

 shows that the result approximates to the expected 1:1:1:1 

 ratio. 



TABLE II 



Culture I Dark 9 I Dark cf Light 9 I Light <? 



Q2 \ 12 12 19 I 15 



Ul 15 17 17 13 



In all the cultures it has been observed that the heterozygous 

 females average a little lighter in color than do the homozygous 

 darks. This difference, however, is not sufficient to allow an 

 accurate separation of the two classes. Dark males are of the 

 same color as the homozygous dark females. 



In October, 1914, I received some banana collected by Mr. B. 

 Schwartz at Fayetteville, Ark. From it there hatched one 

 repleta male, which was of the light type. Bred to light females 

 from culture J, this male produced 133 offspring, all of which 

 were light. 



An examination of the pinned material in my own collection 

 and that of the American Museum of Natural History has shown 

 the existence of a number of specimens which seem to belong to 

 the light type. The following table shows the distribution of the 

 specimens examined. Those marked "not workable," are not 

 in good enough condition to be classified with certainty. 



The table shows the light form to occur in New York, Alabama, 

 Arkansas, California, and Cuba. The Cuban record is of in- 

 terest because the date, 1904, is the earliest of the seven cases. 



