Getting the pitch right is important. About 1 mm can mean 0.8,1,1.1,1.2,1.25,1.3,1.4(?), 1.5 and more. Lay your measuring unit across the device and get a good center to center distance. It is usually easier to measure across several and divide. An end-on view may help. Are the male pins round, square, or blade shaped?
I'd suggest you do a parametric search at Digikey, for instance, and using the connector's pitch (as John's suggested) along with the number of pins, etc, you narrow it down. From there, you could patiently look at the product's pictures listed in the page until you find a match.