H. Onslow 



283 



forms of the allied species tiinlosoma luhricipeda, the Heligoland variety 

 zatima Cr., and var. intermedia Standf , the genetics of which have been 

 worked out by Federluy'. 



to 



J ^ 



T r 



18 W 



A 



'19 K 



TYPE Q O 



10 



20 



30 



(J parent of 

 19/ 



^ parent of 

 19 A' 



40 50 



Number of Insects 

 Fig. 3 (cf. Fig. 4). Curves showing the distribution of the black values 

 of the (J (J , from a wild type family, '18 W ; as well as the values for 

 the ^ (J in the two Fi families, '19 I and K. The value for $ $ of 

 any breeding is given by the line on the right-hand side. 



From matings of rustica x rustica only rustica were obtained. Refer- 

 ence to Figs. 1 and 2 (Family 10 D) shows that the black values of 

 these "pure rustica' all fall round 0'2. Similarly, matings between wild 

 type insects gave nothing but dark males, the colour of which varies 

 considerably within certain limits. The extent of these may be clearly 

 seen from family '18 IT, Figs. 3 and 4. 



The colour variation of several typical F^ hybrids is shown by families 

 19 K and 19 / (see Figs. 3 and 4, also Nos. 3 to 7, PI. XXVII). These 

 hybrids appear to be the same whether the male parent is white or black. 

 Standfuss and Caradja consider that the tnale has more influence in deter- 

 mining the appearance of the otfspring than the female, but this is 

 probably due to the comparatively small numbers they (obtained. In 



1 Federley, H., Hereditas, Vol. i. p. 221, 1920. 



