Similarity in Ascaris lumbricoides and Anopheles stephensi :

In Ascaris, the male is smaller than the female and has a curved posterior end with penial spicules, while the female is larger and straight. So the sexes are clearly distinguishable (sexual dimorphism).
In Anopheles mosquitoes, the male has bushy (plumose) antennae and the female has sparsely hairy antennae; only the female sucks blood. This is also sexual dimorphism.
Ascaris is unsegmented and endoparasitic, while Anopheles is segmented and free-living; Anopheles respires aerobically.
So the similarity is sexual dimorphism.