THE TURTLE-DOVE PATTERN IN THE PHYLOGENY OF PIGEONS. 75 



The Zenaidin/e. 



The genus Nesopelia, represented by a single species (galapagcensis) , is the only 

 member of this subfamily which is fairly evenly chequered over the whole wing 

 (see text-fig. 13), and this condition stamps it as the oldest member. The single 

 specimen which I have examined shows that the feathers of the wing bear, as a rule, 

 each two spots. The outer spot is the larger, and as we pass from the inside outward 

 the spot on the inner web becomes rapidly smaller until at last it is only a marginal 

 streak; feathers beyond this point bear only one chequer, that on the outer web. 

 The chequers are mostly rounded distally. 



On the inner tertials there is a plain asymmetry in position of the two spots as 

 in Zenaidura. The secondaries have black spots, so that here we get the essentials 

 of a posterior wing-band, which is so pronounced a feature of the pattern in some 

 Columba and in still other groups. 



In the mourning-dove (Zenaidura carolinensis) the male (in color, pi. 19, Vol. 

 II) and female differ but slightly, each having about a dozen chequers visible on 

 each side. These are confined to the scapulars (see pi. 24) and to a few feathers at 

 the posterior upper edge of the wing. In the young (pi. 7) the spots are more 

 numerous, though weaker and not so well defined (pi. 25). The ground-color is also 

 weaker in the young. The pale edge is present in the young and absent in the adult. 



The middle and fore parts of the wing in the adult have no visible chequers, 

 but a few concealed ones which may be seen on lifting the overlying feathers. 

 These concealed chequers and the differences between old and young show that the 

 species had its origin in a chequered stock and has suffered a reduction of dark spots. 



In the genus Zenaida the reduction of the spots or chequers has been carried 

 somewhat further. In this respect Z. amabilis (pi. 87) does not differ appreciably 

 from Z. vinaceo-rnfa (pi. 83). The young of this group also have a much greater 

 number of chequers than the adults." The scapulars and tertials have, moreover, 

 smaller spots and fewer double spots (pi. 24) than do those of Zenaidura. 



Some of the juvenal feathers, notably those of the breast, have a rufous mid- 

 streak which near the tip of the feather gradually widens out to include or become 

 continuous with the pale apical edge (this mark was the foundation for the sudden 

 appearance of the broad white "guinea-mark" which appeared in a Zenaida of 

 190G. This mutation is described in Chapter IX. [The reader will find other 

 references to this character in the pages which follow. — Ed.] 



The genus that stands highest in this group is Melopelia. Our white-winged 

 pigeon (M. leucoptera) has practically completed the deletion of spots (text-figs. 8 

 and 14), only a few vestigial traces being discoverable in a single specimen obtained 

 from Jamaica. I do not find such vestiges in white-wings from Mexico and 

 Arizona. Melopelia is therefore to be classed as the latest branch of this subfamily. 



The neck-mark of this species — and of all species of Zenaidinse — presents an 

 interesting and very considerable modification (pi. 26) of the turtle-dove neck-mark. 

 The mark here extends farther upward (closer to the auriculars) and consists of two 

 parts — an uppermost black spot and a structurally modified or iridescent area. 



The young of Melopelia have been found to have rudimentary or obsolescent 

 spots. These are so nearly faded out and so nearly covered that one would not 

 notice them unless looking especially for them. Their color is dark gray, and they 



"For the pattern in a Zenaida X Zenaidura hybrid see plate 20, Vol. II ; for a hybrid composed of these two genera 

 and St. risoria see the same plate. — Ed. 



