RK1 One or more thoracic macrochaetae are very reduced in size, with the scutellar and dorsocentral bristles being most frequently affected. Occasional duplications of macrochaetae are seen.
One or more thoracic bristle much reduced in size; scutellars and dorsocentrals most frequently affected. Occasional bristles duplicated.
Fahmy, 1952.
Extra-bristle phenotype enhanced by duplications for the tip of X with breakpoint between su(s) and tw.