ALA

(Lat. ala, a t^ing.) In Ornithology, the pectoral extremity, the t)ones of which support broad folds of skin, covered with feathers, and are modified for flight. The under part of the base of the wing, where it joins the body, is termed the axilla; the joint between the anti brachium and carpus is termed the flexure or plica. The wing is said to be armed (ala calcar at a) when the carpus bears one or two horny spurs; to be impennate (ala impennata) when provided with equal, lax plumes, unfit for flight; to be elongate (ala elongata) when, in the folded state, it equals or exceeds in length the body from the base of the bill to the root of the tail; to be middle-sized (ala mediocris) when, in the folded state, the extremity covers the base of the tail; to be short (ala brevis) when, in the folded state, the extremity reaches the sides of the coccyx. In Entomology, the wings, or organs of aerial progre ion, are tegumentary productions simply, and consist of a double membrane of a tender and generally transparent consistence, inclosing numerous uervures, or branched tubes of a firmer substance. These organs present considerable differences of form and structure in the different orders of insects, and also vary in number from two to four. [s. 40]