Many head or thoracic macrochaetae are reduced in size or absent. Thoracic and abdominal microchaetae are reduced in number. External male genitalia are abnormal and sometimes completely absent. A melanised exudate is frequently present in the furrow between the mesonotum and the scutellum, near the anterior scutellar bristles. Male viability is less than 10% of wild-type.

Many bristles on head and thorax either reduced in size or absent. Thoracic and abdominal hairs appreciably fewer. External male genitalia invariably abnormal, sometimes completely absent. Melanized exudate frequently present in furrow between mesonotum and scutellum near anterior scutellar bristles. Males sterile; viability less than 10% wild type. RK3.