SEX-LIMITED HEREDITY IN CERTAIN CROSSES. 159 



this period is immediately preceded and followed by a predominance of light- 

 colored offspring; while in both the preceding and succeeding spring-time there is a 

 period in which dark color predominates. In the second mating with alba, the 

 very first and last eggs of the two seasons show infertility (3 cases) or light color 

 (1 case). The more infertile period here, however, would seem to be May or June. 

 In this last mating the first egg showed greater developmental capacity in 5 cases, 

 less in none. In the earlier cross with alba, 2 cases followed the rule and there were 

 2 exceptions ; both of these latter, however, were found in the first clutches of the 

 two seasons embraced by the mating period. The earlier matings of this series — 

 pure risoria and suratensis females — show first eggs of pairs as more fertile in 3 

 cases, less fertile in 1 case. Two further illustrations of and no exceptions to this 

 rule are given by another St. alba female whose record is placed in table 154. 



The bearing of season and fertility upon the dominance of light or dark color 

 may be further noted by reference to the first part of table 154. It will there be 



Table 154. 

 cf alba-ria. X ris.-allia X suraten. XX alba hyb. (T 1); 5/1/03; pale risoria (see pi. 26). 

 9 humilis-risoria hyb. (O 2); 8/7/01; 9/7/05; 49 mo.; darker than above. 



cf .\ 1. 6/21/04 . . . .TH 1 color dark; fertile with risoria (1 pale, and 1 dark cf offspring). 



A 2. 6/23/04 TH 2 dark; toward humilia. 



B 1. 7/10; complexion and down indicated dark color like A 1 and A 2; dead (out of nest) at 3 days. 

 B 2. 7/12; very small— to be while! dead (out of nest) at about 1 to 2 days. 



CI. 8/2 TH3 complexion and down dark, like hutnilis. 



C 2. 8/4; color white! dead (out of nest) at about 10 days. 



D 1. 8/30; small white! died (lice) at 1 day. 



D 2. 9/1; larger light grayish brown; toward earlier darker young; dead at 18 days. 



El. 9/27; no development. 



E 2. 9/29 TH 4 color white ! 



Fl. 10/31 TH5 light pale risoria; dead "autumn 1904." 



F 2. 11/2; no development. 



G 3/14/05; color to be while! dead (thrown from nest) at 1 day. 



d'Hl. 4/4 TH6 dark; toward humilis and suratensis (fertile w. alba); S/14/08 40 



cf H2. 4/6 TH7 dark, suratensis streaks less strong than TH 6 (see pi. 26); matured (G 8) 



tf TH 6 above = alba-ri3. X ris-alha X surat. X X alba XXX hum.-ris. (hyb.) ; 4/4/05; 8/14/08; 40 mo.; dark 

 9 St. alba; from dealer 1906; white. 



cT A. 5/15/06. . . .TH6-A color darfc, near douraca' dead 2/12/08 21 mo 



R '> Q/7(°"® developed to hatching, failed; light down, and complexion of risoria; one, no development. 



C 1. 4/6/07 

 C 2. 4/8/07 

 D 1. 2/5/08 

 D 2. 2/7/08 

 E 1. 3/7/08 



.TH 6-C risoria-like, w. trace reddish (of humilis) : dead 12/C/07 



no development. 



TH 6-D pale light risoria 12/S/09 . 



developed to hatching, failed; complexion ligfU risoria-like. 

 no development (lack of care of cT ? and cold ?). 

 no development (lack of care of d' ? and cold ?). 



<f TH6-A above. 5/15/06; 2/12/08 (tuberculosis); 21 mo.; dark. 

 9 9 St. aiba (l);'from dealer 1906; white. 



9 A. 9/15/07 TH 6-A-A white; fertile alive 4/14/09 19+ mo. 



(G 8, DD) 



' Japanese rings and blond rings had access to the nest of this pair. It was at first thought that a douraca may have 

 left there the egg that hatched this bird; but this consideration was later overruled. — Editor. 



