PRELIMINARY NOTE ON THE RESULTS OF CROSSING 



TWO HEMIPTEROUS SPECIES WITH REFERENCE 



TO THE INHERITANCE OF AN EXCLUSIVELY 



MALE CHARACTER AND ITS BEARING ON 



MODERN CHROMOSOME THEORIES. 



KATHARINE FOOT AND E. C. STROBELL. 



Interest in the studies of the chromosomes has been greatly 

 stimulated during the past few years by the revival of the 

 hypothesis that they are the bearers and distributors of all 

 hereditary characters. Belief in such a fundamental sig- 

 nificance of the chromosomes has led its firmest adherents to 

 interpret every phase of their morphological and physiological 

 expressions into terms of a causal nature, even to the point of 

 claiming that definite chromosomes such as the so-called sex- 

 chromosomesare the determining factors of sex and of all sex- 

 linked characters. 



On the other hand a large number of cytologists have studied 

 the chromosomes from an entirely different point of view- 

 believing that their morphological phases are not to be inter- 

 preted in terms of a causal nature, but like many other organs 

 of the cell, they are the expression rather than the cause of cell 

 activities. 



These opposing interpretations can be strikingly demonstrated 

 by a few quotations from recent papers. Morgan ('u) writes:: 

 "The experiments on Drosophila have led me to two principal 

 conclusions: First, that sex-limited inheritance is explicable on 

 the assumption that one of the material factors of a sex-limited 

 character is carried by the same chromosomes that carry the 

 material factor for femaleness. 



"Second, that the 'association' of certain characters in 

 inheritance is due to the proximity in the chromosomes of the 

 chemical substances (factors) that are essential for the pro- 

 duction of those characters" (pp. 365). 



Wilson ('12) gives the stamp of his approval to Morgan's. 



187 



