In the study reported here, I examined the diagrams that mathematically capable high school students produced in solving applied calculus problems in which a diagram was provided in the problem statement. Analyses of the diagrams contained in written solutions to selected free-response problems from the 1996 BC level Advanced Placement Calculus Examination provided insight into the various ways that students modified these diagrams and constructed new diagrams. I investigated relationships between the frequency or nature of the diagrams produced by high- and low-scoring male and female students and students' problem-solving success. Females, who were less successful in problem solving, produced more diagrams than males. Diagrams constructed or modified by males tended to be simpler than the more elaborate versions produced by females. The Problems from the 1996 BC Level Advanced Placement Calculus Examination are appended. (Contains 6 figures and 8 tables.)