_Eggs._--Lucy's warbler lays from 3 to 7 eggs, but the set usually consists of 4 or 5; the larger sets are rare, but O. W. Howard has found two sets of 7, and several sets of 6 have been recorded. The eggs are ovate to short ovate and have very little lustre. The white or creamy white ground color is finely speckled with shades of "chestnut," "bay," or "auburn." The eggs that have markings in the darker shades of "chestnut" and "bay" frequently have a scattering of minute spots of "brownish drab" that are often lacking on eggs with the lighter markings of "auburn." The spots are usually concentrated at the large end. The measurements of 50 eggs average 14.6 by 11.4 millimeters; the eggs showing the four extremes measure =16.5= by 11.5, 14.6 by =12.0=, =13.2= by 11.2, and 13.7 by =10.7= millimeters. (Harris.) _Young._--The period of incubation seems to be unknown, and I can find no information on the development and care of the young. Evidence points to the conclusion that incubation and brooding are performed entirely by the female, and that at least two broods are reared in a season. Mr. Swarth (1905) says that "several broods are probably raised, as unfinished nests and incomplete sets were found at the same time that broods of young as large as the adults were seen flying about." _Plumages._--Ridgway (1902) says that the young in juvenal plumage are "essentially like adults, but much clearer white beneath; no trace of chestnut on crown; upper tail-coverts ochraceous-buff instead of chestnut; middle and greater wing-coverts tipped with whitish or pale buffy, producing two rather distinct bars." He might have added that the tertials are edged with cinnamon, and that the primaries and rectrices are edged and tipped with white. There is apparently a partial postjuvenal molt, some time during the summer, when all the plumage except the flight feathers, remiges, and rectrices, is renewed. Young birds now become very similar to adults, but can be recognized by the juvenal wings and tail until the edgings wear off. I can find no evidence of a prenuptial molt in either young or old birds. I have seen adults in complete postnuptial molt in August. Fall birds are tinged with brown above and with pale brownish buff below; the chestnut crown patch is concealed by very broad brownish gray tips. Females are not always distinguishable from males, but usually the chestnut on the crown and upper tail coverts is paler and more restricted.