Eyes rough and creased; facets irregular, 15% fewer than normal. Eyes browner than normal; pterine concentration reduced in the eyes and, except for isoxanthopterine, increased in testis sheath. Riboflavin accumulates in Malpighian tubules. Large bristles of head and thorax short, thick, angled, blunt and occasionally reduced to stumps. Arista thick with contorted and supernumerary branches. Scutellum small with groove between it and thorax reduced. Hatchability and larval development normal; larval anal plates swollen and surrounded by melanotic halo. Melanotic anal region persists in pupa; pupa also has melanotic spots elsewhere that may result in nonpigmented areas on the imaginal integument. Extrusion of anterior and posterior spiracles in prepupa incomplete. Many fw⁵⁹ flies die either after 24-30 hr of pupal development or at the time of eclosion. Fecundity of female reduced owing to reduced number of ovarioles. RK2.