A demonstration-quality graphics-assisted debugger is developed for intertask communication in Ada. Based on the static task-specification diagrams of G. Booch (Software Engineering with Ada, Benjamin/Cummings, 1983), the debugger animates the activity of a collection of communicating tasks, and it runs on a DEC GIGI terminal connected to a VAX 11-780 under TeleSoft's partial Ada compiler. The model has been subjected to empirical validation, using undergraduate students as experimental subjects. Subjects were required to debug erroneous tasking programs using both the graphical debugger and a textual one. It is concluded that although the problems to be addressed in the development and evaluation of a graphical debugging tool for Ada tasks are nontrivial, the benefits could be worth the effort.>