H. llAiG ThoiMas 251 



species, the other suggesting the breast pattern of the female parent of 

 the three generations, hut the general effect on the living bird when 

 seen neai- is a striped pattern, and when seen in the distance this melts 

 into a grey effect very diffeient from the non-protective coloration of 

 the inferior parts of the males of both parent species. 



Amongst the males of Series 1 in pedigree another mutation has 

 been observed, namely in the primaries. Gen. nyc. </ primaries have 

 a white ground with J 9 or 20 waving bands of black, which in some 

 feathers are zigzag, the rachis is gi-ey at the quill end, changing to 

 white towanis the outer end. Gen. swinhoei cf has an unpatterned 

 black primary and the rachis black. F^ " BA " are hybrid in colour and 

 pattern with the black rachis of Swinhoe throughout the length of the 

 feather, and this black rachis remains constant and the same in F^ "BBA," 

 F.^ " BBBA " and F^ " BBBA " inter se with one exception. In these 

 three generations, F,, F^ and Ft, the primaries have the waving bands 

 of Gen. nyc. on white ground but these bands are diminished in numbers 

 in some birds, or broken up intnpatchesor into dots and dashes in others, 

 the colour is changed from black to grey, whilst the white area is largely 

 increased. To instance the reduction in number of bands from the pure 

 Silver type of 20, a glance at Plate XLVIII, fig. " Z" shows these 

 reduced to 6, whilst in Plate XLVIII, " F," and in Plate XLVII, " G" 

 and " Q " are good examples of the breaking up into dots and dashes 

 with a vastly increased white area. This umtation of the wing is found 

 correlated with that of the other three mutated areas. In the throat, 

 breast and flank mutations a few birds in F^ " BA," F^ " BBA " and F^ 

 " BBBA " generations showed segregation back to the black feathers of 

 the males of both parent species in one (jr other area, but on only one 

 bird in all four generations was the male Silver pattern found on the 

 primaries. 



Life Hlstory of Sterile Hyi!Rid.s. 



Proceeding in the order indicated, the life history of the sterile 

 hybrids will be sketched. 



Reeves x Versicolor, 1909. 



In this cross infertility was considerable, out of a total of 6.3 eggs 

 39 were infertile, the average of deaths on hatching was not so great,, 

 (j out of 14, and in this cross as in every other, whether sterile or fertile, 

 the sex rati" showed an excess of males over females, for out of 



