The "crescent-egg" a new spontaneous mutant was detected in a white egg strain k37. Studies were carried out the linkage analysis, to investigate phenotypic characteristics and biochemical analysis of haemolymph and ovarian protein. The mutant, ore was independent from 20 linkage groups P(2), Ze(3),L(4), oc(5), sn8), Ia(9), w-1(10), K(11), ch(13), U(14), bl(15), cts(16), bts(17), mln(18), nb(19), oh(20),Lan(21), or(22), tub(23) and Xan(27). The fertilization, hatchability and larval growth were not different from the those of normal eggs. The content and composition of yolk protein were similared to normal eggs. Scanning electron microscopy revealed the areal specific structure in dorsal region of egg-shell of cre mutant. Analysis of chorion protein by isoelectrofocusing(IEF), was resolved no difference in the composite of the chorion protein. We conclude that the egg mutant ere is expressed only in the egg-shape formation and region specific determination.