Second image is male Sphaerophoria scripta (wing length falling short of tip of abdomen is a good pointer). Males of other Sphaerophoria spp. require microscopic examination of genital capsule. First image is a female Sphaerophoria sp. None of the female Sphaerophoria spp. are identifiable to species.
In Sphaerophoria spp., yes; females almost look like a different species altogether. As a rule of thumb, in hoverflies (and flies generally?) the eyes of males tend to touch; in females they are separated. Hope this is helpful?