LÉPIDOPTÉROLOGIE COMPARÉE 48 1 



from defective germs, would accentuate the disturbance in the 

 sexual products. 



A failure of the sexual powers has been observed in many 

 animais to manifest itself in the development of the secondary 

 characters of the opposite sex. Such phenomena we see in the 

 cases of hens past laying, cats, etc., which hâve been castrated 

 and so on. It is but fair to suppose that a similar disturbance. 

 although produced in a vastly différent way, in the sexual pro- 

 ducts of thèse hybrids, causes the development of a mixture of 

 the sexes displayed to such an extraordinary extent in the case 

 of hybrid brooksi. In this explanation it is ail but certain we 

 hâve the real facts of the case. 



The end. 



My best thanks are due to Mrs. Denham, Brooks, Smallman, 

 Burrows and Hull in England, and Herr E. Lange (of Freiberg, 

 Saxony), and Herr Anton Bulovec (of Laibach, Austria), for 

 helping me with material which made my experiments possible. 

 It will be noticed that I hâve recognised this help by applying 

 their names to the hybrids produced. 



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