1914] Beebe: Ontogeny of the White Ibis. 245 



the head and neck. These become exceedingly worn, frayed and 

 faded to a sandy brown. The two former are shed at the regu- 

 lar season for moulting of the species, but not until October or 

 November of the second year is the plumage of the head and 

 neck renewed, that of the crown persisting, as before, until all 

 the other feathers are shed. In the spring the gular pouch be- 

 gins to be developed in the males and the scarlet breeding pig- 

 ment appears, and the bird is ready to breed in fully adult plum- 

 age in the third summer of its life, when two years old. 



The changes in the White Ibis, in the color and pattern of 

 the fleshy parts, eyes and bill during growth are of interest. 

 In the downy chick the irides are hazel, the bill short and 

 straight. The most common type of bill coloring during the 

 first week of life is where it is crossed by five zones of color, 

 two median bands of pinkish flesh, bounded by three equally 

 broad areas of black, the most distal at the very tip of the beak, 

 the second across the center and the third occupying the entire 

 basal area, except for a narrow white frontal line in front of 

 the eyes and extending longitudinally along the margin of the 

 feathered area. There are also two small gular patches of pink 

 and the skin of the chin, between the mandibles, is of the same 

 color. The culmen of the three-day chick measures about 19 

 mm., the lower mandible being several millimetres shorter. This 

 inequality in length, curiously enough, is reflected in the ter- 

 minal band of pigment, which extends considerably farther 

 toward the base than the corresponding dark area on the tip 

 of the upper mandible. 



A good deal of variation is observable in a series of chicks 

 but the five-banded beak is characteristic. The next commonest 

 type is where all but the distal band of black is absent. 



In the chicks hatched in captivity the white loral spots dis- 

 appear before the end of the second week. This transient 

 character is of interest as perhaps representing the permanent 

 facial marking of the related Glossy Ibis {Plegadis autumnalis) . 



On the sixteenth day, July 29th, the increase in the length 

 of the bill was about 12 per cent. On the thirty-fifth day the 

 basal part of the bill had become entirely black, with the ex- 

 ception of the distal band of pink which persisted conspicuously. 



