From the 2560 datasheet, and their identification on the Mega 250 R3 schematic:
1) PB7 >> D13
OC0A/OC1C/PCINT7 (Output Compare and PWM Output A for Timer/Counter0, Output
Compare and PWM Output C for Timer/Counter1 or Pin Change Interrupt 7)
2) PB6 >> D12
OC1B/PCINT6 (Output Compare and PWM Output B for Timer/Counter1 or Pin Change
Interrupt 6)
3) PB5 >> D11
OC1A/PCINT5 (Output Compare and PWM Output A for Timer/Counter1 or Pin Change
Interrupt 5)
4) PB4 >> D10
OC2A/PCINT4 (Output Compare and PWM Output A for Timer/Counter2 or Pin Change
Interrupt 4)
5) PE5 >> D3
INT5/OC3C (External Interrupt 5 Input or Output Compare and PWM Output C for Timer/Counter3)
6) PE4 >> D2
INT4/OC3B (External Interrupt4 Input or Output Compare and PWM Output B for Timer/Counter3)
7) PE3 >> D5
AIN1/OC3A (Analog Comparator Negative Input or Output Compare and PWM Output A for
Timer/Counter3)
8 ) PG5 >> D4
OC0B (Output Compare and PWM Output B for Timer/Counter0)
9) PH6 >> D9
OC2B (Output Compare and PWM Output B for Timer/Counter2)
10) PH5 >> D8
OC4C (Output Compare and PWM Output C for Timer/Counter4)
11) PH4 >> D7
OC4B (Output Compare and PWM Output B for Timer/Counter4)
12) PH3 >> D6
OC4A (Output Compare and PWM Output A for Timer/Counter4)
13) PL5 >> D44
OC5C (Output Compare and PWM Output C for Timer/Counter5)
14) PL4 >> D45
OC5B (Output Compare and PWM Output B for Timer/Counter5)
15) PL3 >> D46
OC5A (Output Compare and PWM Output A for Timer/Counter5)