98 INHERITANCE, FERTILITY, AND SEX IN PIGEONS. 



were the germs of these birds capable of any development. The early part of the 

 season, after a long rest, too, was the time of greatest fertility. Not a single young 

 was reared from 28 tests (table 74). 



It was shown above that a selection of the blackest progeny of dark homers 

 for brother-and-sister matings did not lead to the production of darker progeny, 

 but to a majority of offspring of lighter or redder color than parents or grand- 

 parents; it was indicated also that weakening effects (inbreeding, etc.) were 

 responsible, in part at least, for this result. 



The reverse of the above experiment was also studied. In this experiment 

 light-colored homers (few chequers and small bars) were selected as parents in 

 an effort to obtain offspring of still lighter color. This effort was successful 

 (Chapter II, Vol. I). Table 75 shows, however, that it succeeded best when sire 

 (darker of original parents) was mated to daughter (lightest and narrowest bars), and 

 from eggs laid late in the autumn (August and November); 3 of the 4 eggs then 

 produced gave rise to birds with weaker bars than had any of their known ancestors. ' 

 This situation, moreover, was continued in the succeeding germs which were laid 

 "out of season." Two photographs (pi. 16) assist in making clear the measure of 

 success attained in this experiment. In the first mating listed in table 75 the parents 

 were unrelated; the lightest colored young of this mating develojied from eggs 

 laid outside of the usual breeding season, during autumn and winter. 



Another mating for a period of 5 years was made in the effort to produce 2- 

 barred homers from 3-barred parents one of whom had chequers as well as 3 bars. 



' The fourth had bars equal to the least developed bars of a parent, and was of lighter color. 



Explanation of Plate 16. 



A. Two Juvenal homer.s, brother ami sister to the pair figured helow. Halnhed from a clutch {H 1 



and H 2) just preceding young of fig. B; also the i)aniit< df tlu -c two jiairs of j'oung. 



On the extreme left is H 1 in juvenal plumage: it prcscnN .mui In r (h^iimi ~i( p i..\\;iii|s thr iimiplete obliteration 

 of the bars of the wings and .'ilsn of the tnil. 'I'his bird ii;is a lypical Imiuk r hiiiM «v l,,iiii, l>iil has a single feather 

 turned outward (I'lill-liki' ■ in I \if niiiMli' of l Im' u|i|irr l>;vast. 'i'hc ^i'iiunil-ci)lnr is a ilislinci shade Hghtcr than the 

 ordinary rock-gray. lliMd ami nrcL .lr('al('>ll\ Imlilri' ihan in rucks, a shade uf rusly liniwnish ui the neck. In ]ilaec 

 of the subapical bkek 1. md m l lie i ail ileiv i> a very pah' wliilisli-gray hand, about ITnnii. in width, with an ajucal 

 dusky-gray border a 1 "11 It , mm, in wall li. Kiuiip whitish gray. 



The wing-bars \u\\r Ui<\ ihe bknk almost wholly, leaving a paler gray than in the rest of the wing; and this 

 paler gray is lightlx Iniielied wiih l.r.iwnish and bordered posteriorly wdth a narrow, ill-defined dusky line, varying 

 from 1 to 2 mm. in widlli. I'.uih hai- are in essentially the same rnnditinn. but we may note tliat in the imsterior 

 bar the black is praelieall\- a laml Hare ..f hr.iunisl,. in ihe l.allal- Ilil- pn~le)in, l,ai i- iieallx of li.e .ame enlnr as 

 the anterior bar, bnl c.n l hi' mnri :; .n- I lei i lal- L' lu :i .hisk\' ■•IniHlameniii hai- " m.-^ ilie miier ueli ol i he leal hers. 

 This bird mnh,, „ „..,,■ „i,rn,.,rh In ,,„„pl,l. Ins, „J ,v, ,„j-ha IS . M a lillle ilislanee il appeal- In have no b.ars, or only 

 shadowy indieai mn- of lo-i liais. 



On the e\i I. iiM ii^hi 1- // ,', it is clear rock-gray in color, and has narrow black bars about ihe same as its mother. 

 It has the iisii.il -I ilia plea I lail-liaud; the rump is white. The anterior bar has a width of nnn. on the inner coverts 

 and gradually narrows to 5 mm. just below the middle of the row of coverts. The posterior bar (on Ti inner tertials) 

 has a greatest width of 17 mm. on the fourth tertial; it becomes freckled with gray on the .sovcnl li tertial and is nearly 

 obliterated on the eighth. 



The two parents are shown at the center of the figure. 



B. Juvenal homers (/ 1 and / 2) with light color (in / 1) and witii wing-bars rcducctl. Photographed 



Jan. 19, 1910, at the age of 6 weeks 4 days. 



These birds from sire mated to daughter i table T.'.', and tr uii^ laid in very laie aiiliinm, Nov. l."i to 17, I'.KIU. 



Juvenal / / (on left) has rock-gray <-olor \Mlh fom Minan^h l.laek spols on ihe outer web of (he inner lerlials. 

 The first and fourth spots are a little smaller and ueaki i or Ihinni r ihan Ihe second and llurd, whieli measure 111 by 

 8 mm. and 13 by 8 mm., respectively. Below these spots tf lerc arc only scattered freckles which are too weak to ligure 

 as spots. The appearance is thus practically what we see in the stock-dove iC ini<i,\. The anterior liar has no spots, 

 but just freckles enough to indicate a trace of a bar when closely e.\amined. 



Juvenal / 2, color almost white or silver gray. 



