|{. II AK! ^rilOMAS 277 



" BBBA," F.,,. " n," ^. I'atUTiicd white: nichis black froui (juill cud, 



two-thirds (if length. 

 F.,. "Kr ^. Slightly pattfi-ncd wiutc: racliisl)i:xok, -it c|iii1l 

 end. 

 „ F^. " fr," ,/. Patterned while : Vdcliia white. 



F.J. "y/'cf. Patterned white : 7-(fc/M.9 ?Wn'te. 

 "BBBA" inter ne, F,. " IL' ^. Patterned the whole length of the 



feather. Rachis black from ijuill to half the 

 length. 

 „ Fj. "N"(f. Unpatterned white. Rachi.s black 



for three inches at quill end. 

 „ „ F^. "D,"(^. Patterned throughout length of 



feather. Rachis black for two-thirds of 

 length from quill. 

 „ „ Fi. " L," cT. Heavily patterned quill to tip on 



outer vanes, slightly patterned on inner 

 vanes. Rachis dark throughout from quill 

 to tip. 



Note. F-t. " C," (/ , has the central rectrix pure Swinhoe type. 

 It is observed also in this bird that one thigh-tuft feather was the exact 

 pattern of the female Swinhoe breast. 



It is evident that as amongst the female Silvers, so also amongst the 

 male Silvers considerable diversity of pattern exists in the central 

 rectrices, but it is e(jually evident that in F^ inter se we have a hybrid 

 or mutating condition in which there is evidence of the working ol' 

 Mendel's law. 



DESCRIPTION OF PLATES. 



(All figures are natural size unless the contrary is stated.) 

 STERILE HYBRIDS. 



PLATE XXXIV. 



Tail coverts. 



Transmission of struetme bj- femule parent to male olTspring : 

 Fig. 1. v. formosanua S . 

 Fig. 2. P. reevesi <S . 

 Fig. 3. V. versicolor d . 

 Fig. 4. t\ (Reevesi ? x Forniosanus i ) s . 



