http://www.nikonchat.com/nikon-ed-55-200mm/

Can the Nikon 55 – 200mm ED AF-S DX F4-5.6G lens fit Nikon D40 camera?
starting in photography
If Get fit and full function of it. It is an AF-s series lens with an autofocus means Silent Wave motor in the lens, and a DX format work with APS size sensors c and in the D40, but crops in a full size or FX sensor size. Ed says he has extra-dispersion glass low in the lens elements. and G means that the lens has no aperture ring mesh mesh opening is controlled by the camera body. Hope this helps
Nikon D40 doublekitlens unboxing