286 The Inheritance of Wing-Colour in Lepidoptera 



By pairing the F^ hybrids back to type insects, two fairly distinct 

 classes were obtained; insects as dark as type or darker with black 

 values above 40, and intermediate insects with black values consider- 

 ably below 4*0 sometimes even falling below 0'5. Reference to Figs. 7 to 

 10 will show how clearly these two forms segregate. In family '19 C 

 (Fig. 7) there is a gap of over two colour units between the RR and the 

 DR insects, and in family '18 A (Fig. 9) the gap is as large. In the other 

 families segregation is scarcely less complete. There appears to be no 

 difference in the colour of the offspring, whether the type insect is the 

 male or the female parent. 



i^i X Type. 



[DE X ER]. 



Imagines 



