The following information was provided by Janna McLean, Bethel College. 
Df(2L)Sd-Rev8a-4 is a deletion of 37BC;38BC produced to delete RanGAPSd. It also deletes pr.
The deletion was induced in a chromosome generated by Hiraizumi et al. (1980; FBrf0034876) with the mutations RanGAPSd Rspss M(SD)1 bw1. Because the combination of RanGAPSd and Rspss creates a "suicide chromosome" that will be inherited by very few progeny of males carrying the chromosome, it was possible to screen for loss of Segregation Distortion from deletion of RanGAPSd along with deletion of the nearby pr gene.