RESULTS OF HYBRIDIZING RING-DOVES. 317 



Some of these data are given in other form in Table XXII. 

 where each mating is referred to the table which describes it. 



The periods between laying and hatching may be summarized 

 as follows in Table XXI 1 1. 



TABLE XXIII. 



Number of Individuals. 

 Period. Stock. Blond Hybrids. White Hybrids. 



First egg. 15 days. 5 26 12 



16 " 2 8 9 



17 " i 

 19 " I 



Second egg. 14 days. 5 22 14 



15 " 33 



16 " 

 18 " 



It will be noticed that no cases of more than two eggs in a 

 clutch occurred. 



The idea has existed that the first eggs in a pigeon clutch 

 usually give rise to males, though I know of no studies which 

 would support this idea. An inspection of the data in Table 

 XXI. proves this assumption to be without foundation with 

 ring-doves at least. A summary of the results from those 

 matings where the offspring were not mostly either males or 

 females is given below. The matings from which the statistics 

 were taken are as follows: Nos. 2, 8-10, 15, 16, 22, 24-33, 35, 37 

 -40, 42 and 44. 



First egg Male 13 



" Female 28 



Second egg Male 1 5 



" Female 1 5 



It is obvious that ring-doves, at least, do not show any corre- 

 lation between sex and the order of laying or of hatching. Cole 

 ( f u) obtained similar results with tumbler pigeons. 



IV. SUMMARY. 



1. Hybrids between blond male ring-doves and white female 

 ring-doves are all blonds and they are mostly males. 



2. The offspring of the reciprocal cross are about equally 

 blonds or whites, but all of the white birds are females. White- 

 ness and the characters associated with it are sex-linked. Al- 



