X-linked recessive traits in humans (or in drosophila) are observed
in more males than females
in more females than males
in males and females equally
in different distributions depending on the trait

in more males than females

Explanation:

The reason behind that is that females in mammalians and drosophila, are homogametic sex. It means that every female will have to two brother X-chromosomes (XX).

On the other and males only have one X and one Y- chromosome (heterogametic sex).

Because of this, females have two copies of one gene, which allows the possibility of one recessive allele of a gen X-linked to be eclipsed by the presence of a dominant allele. So in females, there are three possibilities: both X-chromosomes recessive homozygotic, only one allele recessive (heterozygotic) or dominant homozygotic

In males history is different. Males only have 1 copy of the gen contained, so the copy that he/it possesses will be the only being expressed.

not sure if this is what you'r looking for eubacteria and archaebacteria