ptilo-, ptil-, ptilono- +

A single neossoptile, without rachis (shaft of a feather), formed by precocious development of the barbs of the teleoptile.

Prepenna following protoptile and succeeded by metaptile or by teleoptile.

A plumose (feather; having feathers; feather-like) penna (a contour feather of birds, as distinguished from plume or down feathers), or simply a feather.

1. Regarding young birds, a down feather which forms the natal plumage.
2. Feathers of nestlings; down feathers, or the down of newly hatched birds.

The plumage of the newborn chick is downy, called neossoptile; the development which follows is termed teleoptile.

Juvenal plumage, is frequently distinct from that of the adult bird; is often drab, streaked, or spotted, and thus camouflages the young bird.

The primary prepenna (a nestling down feather which is succeeded by an adult contour feather), succeeded by mesoptile.

A head vesicle or bladder-like expansion of the head of a fly emerging from a pupa.

There is a special structure which is used to help an emerging adult fly break free of the puparium. This structure is an inflatable membranous sac called the ptilinum which protrudes from the face, above the antennae.

The inflation of the ptilinum (using fluid hemolymph, rather than air) creates pressure along the line of weakness in the puparium (pupa casing or resting stage), which then bursts open along the seam to allow an adult fly to escape.

The beginning of the growth of feathers.

In ornithology, a reference to birds hatched with a complete covering of down (with soft fluffy feathers).

A reference to a bird that has legs and toes which are feathered.

1. A disease of the eyelids in which their edges become swollen and inflamed and the eyelashes fall off.
2. Pterylosis (arrangement of pterylae [bird's feather tracts or skin areas on which feathers grow] and apteria [naked or down-covered surfaces between pterylae] in birds).
3. Etymology: Greek ptilosis (from ptil(on), "feather, plumage" plus -osis, "a disease".

A feather of definitive plumage.