So after saving the female Krogan, the Krogan leader sends you to a planet where there is suspected Rachni activity and some of his scouts have dissapeared. Now right before you get to see the queen there is a dead Krogan behind some webbing, and if you inspect him Sheppard will say something about delivering a message to an Asari female in the Citadel. Now I have checked my logs for the quest but i can't find it anywhere and I can't find the woman either. Does anyone know where to find her?
She's in one of the shops in the Presidium Commons. There are two shops at the place were EDI and Joker previously were (before the Cerberus attack). In one of those shops is the woman you're looking for.
Here's the map of the area, the woman is at my position:
And here's an image showing you the Asari you need to give the message to: