Actually it is a female! In cuckoo wasps both sexes have same number of flagellomeres. Males really have somewhat longer flagellomeres also in cuckoo wasps but for length comparison you need to compare both sexes of same species. The length of flagellomeres is variable between different species. Sexes of cuckoo wasps are often quite difficult to separate.
Usually ovipositor is what gives away the sex of cuckoo wasp. In this case pointed tip is also visible from the ventral side suggesting it is a female (ignore the obtuse third gastral tergum). However the genus Elampus is exceptional since there is a good character for separating sexes. Only females have a row of short erect setae laterally along genal margin behind the eye. These setae are visible on the ventral view.

Thanks for explaining this! OK, I think that the "info" tab for this family might need more (accurate) info.