THE ENTOMOLOGIST 



Vol. XXXI.] JULY, 1898. [No. 422. 



HYBBIDIZATION. 



In ' Science Progress ' for April there is an important paper 

 by Dr. Dixey on " Becent Experiments in Hybridization con- 

 ducted by Dr. Standfuss, of Zurich." Beferring to fertile and 

 infertile pairings between species of Lepidoptera, our author 

 remarks that in five cases only male specimens resulted, whilst 

 in five others only female examples were reared, and these latter 

 " contained no eggs capable of development." Seven other 

 crosses again produced both males and females, but the former 

 were in the majority and the latter were sterile. After referring 

 to still five other crosssings, he mentions that according to 

 Standfuss "In no single instance has the female of any true 

 hybrid among Lepidoptera been shown experimentally to be 

 fertile." All who are studying the facts of hybridization will no 

 doubt make a point of seeing this valuable contribution to the 

 subject, but in the meanwhile we venture to give one or two 

 extracts therefrom that will interest readers who rear the species 

 mentioned. 



"Aberrations. 



" Some very remarkable facts are recorded as to the effect of 

 crossing a sport or aberration with its parent form. The result, 

 which is entirely different from that which follows the crossing 

 of distinct species, or even of local races, may be broadly stated 

 as follows : When an aberration is crossed with its parent form 

 the issue is sharply divided, in both sexes, into specimens of the 

 aberration and of the normal form of the species. Thus in the 

 dark aberration zatima, Cr., of Spilosoma lubricipeda, Esp., there 

 are many degrees from the least dark form of the aberration 

 (ab. intermedia, Bang-Haas) up to the darkest (ab. deschangei, 

 Depuis) ; but no transitional forms occur to bridge over the wide 

 gap between intermedia and lubricipeda, nor can they be produced 

 by crossing these two. ' It seems,' so Standfuss expresses it, 



ENTOM. JULY, 1898. P 



